Inbred maize line PHDWA

ABSTRACT

A novel inbred maize line designated PHDWA and seed, plants and plant parts thereof. Methods for producing a maize plant that comprise crossing inbred maize line PHDWA with another maize plant. Methods for producing a maize plant containing in its genetic material one or more traits introgressed into PHDWA through backcross conversion and/or transformation, and to the maize seed, plant and plant part produced thereby. Hybrid maize seed, plant or plant part produced by crossing the inbred line PHDWA or a trait conversion of PHDWA with another maize line. Inbred maize lines derived from inbred maize line PHDWA, methods for producing other inbred maize lines derived from inbred maize line PHDWA and the inbred maize lines and their parts derived by the use of those methods.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 11/343,391, now U.S. Pat. No. 7,227,063, filed on Jan. 31, 2006, the content of which is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

This invention relates generally to the field of maize breeding, specifically relating to an inbred maize line designated PHDWA.

BACKGROUND OF THE INVENTION

The goal of plant breeding is to combine, in a single variety or hybrid, various desirable traits. For field crops, these traits may include resistance to diseases and insects, resistance to heat and drought, reducing the time to crop maturity, greater yield, and better agronomic quality. With mechanical harvesting of many crops, uniformity of plant characteristics such as germination, stand establishment, growth rate, maturity, plant height and ear height, is important. Traditional plant breeding is an important tool in developing new and improved commercial crops.

SUMMARY OF THE INVENTION

According to the invention, there is provided a novel inbred maize line, designated PHDWA and processes for making PHDWA. This invention relates to seed of inbred maize line PHDWA, to the plants of inbred maize line PHDWA, to plant parts of inbred maize line PHDWA, and to processes for making a maize plant that comprise crossing inbred maize line PHDWA with another maize plant. This invention also relates to processes for making a maize plant containing in its genetic material one or more traits introgressed into PHDWA through backcross conversion and/or transformation, and to the maize seed, plant and plant part produced by such introgression. This invention further relates to a hybrid maize seed, plant or plant part produced by crossing the inbred line PHDWA or an introgressed trait conversion of PHDWA with another maize line. This invention also relates to inbred maize lines derived from inbred maize line PHDWA to processes for making other inbred maize lines derived from inbred maize line PHDWA and to the inbred maize lines and their parts derived by the use of those processes.

Definitions

Certain definitions used in the specification are provided below. Also in the examples that follow, a number of terms are used herein. In order to provide a clear and consistent understanding of the specification and claims, including the scope to be given such terms, the following definitions are provided. NOTE: ABS is in absolute terms and % MN is percent of the mean for the experiments in which the inbred or hybrid was grown. PCT designates that the trait is calculated as a percentage. % NOT designates the percentage of plants that did not exhibit a trait. For example, STKLDG % NOT is the percentage of plants in a plot that were not stalk lodged. These designators will follow the descriptors to denote how the values are to be interpreted. Below are the descriptors used in the data tables included herein.

ABTSTK=ARTIFICIAL BRITTLE STALK. A count of the number of “snapped” plants per plot following machine snapping. A snapped plant has its stalk completely snapped at a node between the base of the plant and the node above the ear. Expressed as percent of plants that did not snap.

ALLELE. Any of one or more alternative forms of a genetic sequence. Typically, in a diploid cell or organism, the two alleles of a given sequence typically occupy corresponding loci on a pair of homologous chromosomes.

ALTER. The utilization of up-regulation, down-regulation, or gene silencing.

ANTHESIS. The time of a flower's opening.

ANT ROT=ANTHRACNOSE STALK ROT (Colletotrichum graminicola). A 1 to 9 visual rating indicating the resistance to Anthracnose Stalk Rot. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

BACKCROSSING. Process in which a breeder crosses a hybrid progeny line back to one of the parental genotypes one or more times.

BARPLT=BARREN PLANTS. The percent of plants per plot that were not barren (lack ears).

BORBMN=ARTIFICIAL BRITTLE STALK MEAN. The mean percent of plants not “snapped” in a plot following artificial selection pressure. A snapped plant has its stalk completely snapped at a node between the base of the plant and the node above the ear. Expressed as percent of plants that did not snap. A high number is good and indicates tolerance to brittle snapping.

BRENGMN=BRITTLE STALK ENERGY MEAN. The mean amount of energy per unit area needed to artificially brittle snap a corn stalk. A high number is good and indicates tolerance to brittle snapping.

BREEDING. The genetic manipulation of living organisms.

BREEDING CROSS. A cross to introduce new genetic material into a plant for the development of a new variety. For example, one could cross plant A with plant B, wherein plant B would be genetically different from plant A. After the breeding cross, the resulting F1 plants could then be selfed or sibbed for one, two, three or more times (F1, F2, F3, etc.) until a new inbred variety is developed. For clarification, such new inbred varieties would be within a pedigree distance of one breeding cross of plants A and B. The process described above would be referred to as one breeding cycle.

BRTSTK=BRITTLE STALKS. This is a measure of the stalk breakage near the time of pollination, and is an indication of whether a hybrid or inbred would snap or break near the time of flowering under severe winds. Data are presented as percentage of plants that did not snap. Data are collected only when sufficient selection pressure exists in the experiment measured.

CELL. Cell as used herein includes a plant cell, whether isolated, in tissue culture or incorporated in a plant or plant part.

CLDTST=COLD TEST. The percent of plants that germinate under cold test conditions.

CLN=CORN LETHAL NECROSIS. Synergistic interaction of maize chlorotic mottle virus (MCMV) in combination with either maize dwarf mosaic virus (MDMV-A or MDMV-B) or wheat streak mosaic virus (WSMV). A 1 to 9 visual rating indicating the resistance to Corn Lethal Necrosis. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

COMRST=COMMON RUST (Puccinia sorghi). A 1 to 9 visual rating indicating the resistance to Common Rust. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

CROSS POLLINATION. A plant is cross pollinated if the pollen comes from a flower on a different plant from a different family or line. Cross pollination excludes sib and self pollination.

CROSS. As used herein, the term “cross” or “crossing” can refer to a simple X by Y cross, or the process of backcrossing, depending on the context.

D/D=DRYDOWN. This represents the relative rate at which a hybrid will reach acceptable harvest moisture compared to other hybrids on a 1 to 9 rating scale. A high score indicates a hybrid that dries relatively fast while a low score indicates a hybrid that dries slowly.

DIPERS=DIPLODIA EAR MOLD SCORES (Diplodia maydis and Diplodia macrospora). A 1 to 9 visual rating indicating the resistance to Diplodia Ear Mold. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

DIPLOID PLANT PART. Refers to a plant part or cell that has the same diploid genotype as PHDWA.

DIPROT=DIPLODIA STALK ROT SCORE. Score of stalk rot severity due to Diplodia (Diplodia maydis). Expressed as a 1 to 9 score with 9 being highly resistant. Data are collected only when sufficient selection pressure exists in the experiment measured.

DRPEAR=DROPPED EARS. A measure of the number of dropped ears per plot and represents the percentage of plants that did not drop ears prior to harvest. Data are collected only when sufficient selection pressure exists in the experiment measured.

D/T=DROUGHT TOLERANCE. This represents a 1 to 9 rating for drought tolerance, and is based on data obtained under stress conditions. A high score indicates good drought tolerance and a low score indicates poor drought tolerance. Data are collected only when sufficient selection pressure exists in the experiment measured.

EARHT=EAR HEIGHT. The ear height is a measure from the ground to the highest placed developed ear node attachment and is measured in centimeters.

EARMLD=GENERAL EAR MOLD. Visual rating (1 to 9 score) where a 1 is very susceptible and a 9 is very resistant. This is based on overall rating for ear mold of mature ears without determining the specific mold organism, and may not be predictive for a specific ear mold. Data are collected only when sufficient selection pressure exists in the experiment measured.

EARSZ=EAR SIZE. A 1 to 9 visual rating of ear size. The higher the rating the larger the ear size.

EBTSTK=EARLY BRITTLE STALK. A count of the number of “snapped” plants per plot following severe winds when the corn plant is experiencing very rapid vegetative growth in the V5-V8 stage. Expressed as percent of plants that did not snap. Data are collected only when sufficient selection pressure exists in the experiment measured.

ECB1LF=EUROPEAN CORN BORER FIRST GENERATION LEAF FEEDING (Ostrinia nubilalis). A 1 to 9 visual rating indicating the resistance to preflowering leaf feeding by first generation European Corn Borer. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

ECB2IT=EUROPEAN CORN BORER SECOND GENERATION INCHES OF TUNNELING (Ostrinia nubilalis). Average inches of tunneling per plant in the stalk. Data are collected only when sufficient selection pressure exists in the experiment measured.

ECB2SC=EUROPEAN CORN BORER SECOND GENERATION (Ostrinia nubilalis). A 1 to 9 visual rating indicating post flowering degree of stalk breakage and other evidence of feeding by second generation European Corn Borer. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

ECBDPE=EUROPEAN CORN BORER DROPPED EARS (Ostrinia nubilalis). Dropped ears due to European Corn Borer. Percentage of plants that did not drop ears under second generation European Corn Borer infestation. Data are collected only when sufficient selection pressure exists in the experiment measured.

ECBLSI=EUROPEAN CORN BORER LATE SEASON INTACT (Ostrinia nubilalis). A 1 to 9 visual rating indicating late season intactness of the corn plant given damage (stalk breakage above and below the top ear) caused primarily by 2^(nd) and/or 3^(rd) generation ECB larval feeding before harvest. A higher score is good and indicates more intact plants. Data are collected only when sufficient selection pressure exists in the experiment measured.

EGRWTH=EARLY GROWTH. This is a measure of the relative height and size of a corn seedling at the 2-4 leaf stage of growth. This is a visual rating (1 to 9), with 1 being weak or slow growth, 5 being average growth and 9 being strong growth. Taller plants, wider leaves, more green mass and darker color constitute higher score. Data are collected only when sufficient selection pressure exists in the experiment measured.

ELITE INBRED. An inbred that contributed desirable qualities when used to produce commercial hybrids. An elite inbred may also be used in further breeding for the purpose of developing further improved varieties.

ERTLDG=EARLY ROOT LODGING. The percentage of plants that do not root lodge prior to or around anthesis; plants that lean from the vertical axis at an approximately 30 degree angle or greater would be counted as root lodged. Data are collected only when sufficient selection pressure exists in the experiment measured.

ERTLPN=EARLY ROOT LODGING. An estimate of the percentage of plants that do not root lodge prior to or around anthesis; plants that lean from the vertical axis at an approximately 30 degree angle or greater would be considered as root lodged. Data are collected only when sufficient selection pressure exists in the experiment measured.

ERTLSC=EARLY ROOT LODGING SCORE. Score for severity of plants that lean from a vertical axis at an approximate 30 degree angle or greater which typically results from strong winds prior to or around flowering recorded within 2 weeks of a wind event. Expressed as a 1 to 9 score with 9 being no lodging. Data are collected only when sufficient selection pressure exists in the experiment measured.

ESTCNT=EARLY STAND COUNT. This is a measure of the stand establishment in the spring and represents the number of plants that emerge on per plot basis for the inbred or hybrid.

EYESPT=EYE SPOT (Kabatiella zeae or Aureobasidium zeae). A 1 to 9 visual rating indicating the resistance to Eye Spot. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

FUSERS=FUSARIUM EAR ROT SCORE (Fusarium moniliforme or Fusarium subglutinans). A 1 to 9 visual rating indicating the resistance to Fusarium Ear Rot. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

GDU=GROWING DEGREE UNITS. Using the Barger Heat Unit Theory, which assumes that maize growth occurs in the temperature range 50 degrees F. −86 degrees F. and that temperatures outside this range slow down growth; the maximum daily heat unit accumulation is 36 and the minimum daily heat unit accumulation is 0. The seasonal accumulation of GDU is a major factor in determining maturity zones.

GDUSHD=GDU TO SHED. The number of growing degree units (GDUs) or heat units required for an inbred line or hybrid to have approximately 50 percent of the plants shedding pollen and is measured from the time of planting. Growing degree units are calculated by the Barger Method, where the heat units for a 24-hour period are:

${GDU} = {\frac{\left( {{Max}.\mspace{11mu}{temp}.{+ {{Min}.\mspace{11mu}{temp}.}}} \right)}{2} - 50}$

The highest maximum temperature used is 86 degrees F. and the lowest minimum temperature used is 50 degrees F. For each inbred or hybrid it takes a certain number of GDUs to reach various stages of plant development.

GDUSLK=GDU TO SILK. The number of growing degree units required for an inbred line or hybrid to have approximately 50 percent of the plants with silk emergence from time of planting. Growing degree units are calculated by the Barger Method as given in GDU SHD definition.

GENE SILENCING. The interruption or suppression of the expression of a gene at the level of transcription or translation.

GENOTYPE. Refers to the genetic constitution of a cell or organism.

GIBERS=GIBBERELLA EAR ROT (PINK MOLD) (Gibberella zeae). A 1 to 9 visual rating indicating the resistance to Gibberella Ear Rot. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

GIBROT=GIBBERELLA STALK ROT SCORE. Score of stalk rot severity due to Gibberella (Gibberella zeae). Expressed as a 1 to 9 score with 9 being highly resistant. Data are collected only when sufficient selection pressure exists in the experiment measured.

GLFSPT=GRAY LEAF SPOT (Cercospora zeae-maydis). A 1 to 9 visual rating indicating the resistance to Gray Leaf Spot. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

GOSWLT=GOSS' WILT (Corynebacterium nebraskense). A 1 to 9 visual rating indicating the resistance to Goss' Wilt. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

GRNAPP=GRAIN APPEARANCE. This is a 1 to 9 rating for the general appearance of the shelled grain as it is harvested based on such factors as the color of harvested grain, any mold on the grain, and any cracked grain. High scores indicate good grain visual quality.

HAPLOID PLANT PART. Refers to a plant part or cell that has the same haploid genotype as PHDWA.

HCBLT=HELMINTHOSPORIUM CARBONUM LEAF BLIGHT (Helminthosporium carbonum). A 1 to 9 visual rating indicating the resistance to Helminthosporium infection. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

HD SMT=HEAD SMUT (Sphacelotheca reiliana). This score indicates the percentage of plants not infected. Data are collected only when sufficient selection pressure exists in the experiment measured.

HSKCVR=HUSK COVER. A 1 to 9 score based on performance relative to key checks, with a score of 1 indicating very short husks, tip of ear and kernels showing; 5 is intermediate coverage of the ear under most conditions, sometimes with thin husk; and a 9 has husks extending and closed beyond the tip of the ear. Scoring can best be done near physiological maturity stage or any time during dry down until harvested.

INBRED. A line developed through inbreeding or doubled haploidy that preferably comprises homozygous alleles at about 95% or more of its loci.

INC D/A=GROSS INCOME (DOLLARS PER ACRE). Relative income per acre assuming drying costs of two cents per point above 15.5 percent harvest moisture and current market price per bushel.

INCOME/ACRE. Income advantage of hybrid to be patented over other hybrid on per acre basis.

INC ADV=GROSS INCOME ADVANTAGE. Gross income advantage of variety #1 over variety #2.

INTROGRESSION. The process of transferring genetic material from one genotype to another.

KSZDCD=KERNEL SIZE DISCARD. The percent of discard seed; calculated as the sum of discarded tip kernels and extra large kernels.

LINKAGE. Refers to a phenomenon wherein alleles on the same chromosome tend to segregate together more often than expected by chance if their transmission was independent.

LINKAGE DISEQUILIBRIUM. Refers to a phenomenon wherein alleles tend to remain together in linkage groups when segregating from parents to offspring, with a greater frequency than expected from their individual frequencies.

LOCUS. A defined segment of DNA.

L/POP=YIELD AT LOW DENSITY. Yield ability at relatively low plant densities on a 1 to 9 relative system with a higher number indicating the hybrid responds well to low plant densities for yield relative to other hybrids. A 1, 5, and 9 would represent very poor, average, and very good yield response, respectively, to low plant density.

LRTLDG=LATE ROOT LODGING. The percentage of plants that do not root lodge after anthesis through harvest; plants that lean from the vertical axis at an approximately 30 degree angle or greater would be counted as root lodged. Data are collected only when sufficient selection pressure exists in the experiment measured.

LRTLPN=LATE ROOT LODGING. An estimate of the percentage of plants that do not root lodge after anthesis through harvest; plants that lean from the vertical axis at an approximately 30 degree angle or greater would be considered as root lodged. Data are collected only when sufficient selection pressure exists in the experiment measured.

LRTLSC=LATE ROOT LODGING SCORE. Score for severity of plants that lean from a vertical axis at an approximate 30 degree angle or greater which typically results from strong winds after flowering. Recorded prior to harvest when a root-lodging event has occurred. This lodging results in plants that are leaned or “lodged” over at the base of the plant and do not straighten or “goose-neck” back to a vertical position. Expressed as a 1 to 9 score with 9 being no lodging. Data are collected only when sufficient selection pressure exists in the experiment measured.

MDMCPX=MAIZE DWARF MOSAIC COMPLEX (MDMV=Maize Dwarf Mosaic Virus and MCDV=Maize Chlorotic Dwarf Virus). A 1 to 9 visual rating indicating the resistance to Maize Dwarf Mosaic Complex. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

MST=HARVEST MOISTURE. The moisture is the actual percentage moisture of the grain at harvest.

MSTADV=MOISTURE ADVANTAGE. The moisture advantage of variety #1 over variety #2 as calculated by: MOISTURE of variety #2—MOISTURE of variety #1=MOISTURE ADVANTAGE of variety #1.

NEI DISTANCE. A quantitative measure of percent similarity between two lines. Nei's distance between lines A and B can be defined as 1−(2*number alleles in common/(number alleles in A+number alleles in B). For example, if lines A and B are the same for 95 out of 100 alleles, the Nei distance would be 0.05. If lines A and B are the same for 98 out of 100 alleles, the Nei distance would be 0.02. Free software for calculating Nei distance is available on the internet at multiple locations such as, for example, at: evolution.genetics.washington.edu/phylip.html. See Nei, Proc Natl Acad Sci, 76:5269-5273 (1979) which is incorporated by reference for this purpose.

NLFBLT=NORTHERN LEAF BLIGHT (Helminthosporium turcicum or Exserohilum turcicum). A 1 to 9 visual rating indicating the resistance to Northern Leaf Blight. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

OILT=GRAIN OIL. Absolute value of oil content of the kernel as predicted by Near-infrared Transmittance and expressed as a percent of dry matter.

PEDIGREE DISTANCE. Relationship among generations based on their ancestral links as evidenced in pedigrees. May be measured by the distance of the pedigree from a given starting point in the ancestry.

PERCENT IDENTITY. Percent identity as used herein refers to the comparison of the homozygous alleles of two inbred lines. Each inbred plant will have the same allele (and therefore be homozygous) at almost all of their loci. Percent identity is determined by comparing a statistically significant number of the homozygous alleles of two inbred lines. For example, a percent identity of 90% between inbred PHDWA and other inbred line means that the two inbred lines have the same allele at 90% of their loci.

PERCENT SIMILARITY. Percent similarity as used herein refers to the comparison of the homozygous alleles of an inbred line with another plant. The homozygous alleles of PHDWA are compared with the alleles of a non-inbred plant, such as a hybrid, and if the allele of the inbred matches at least one of the alleles from the hybrid then they are scored as similar. Percent similarity is determined by comparing a statistically significant number of loci and recording the number of loci with similar alleles as a percentage. For example, a percent similarity of 90% between inbred PHDWA and a hybrid maize plant means that the inbred line matches at least one of the hybrid alleles at 90% of the loci. In the case of a hybrid produced from PHDWA as the male or female parent, such hybrid will comprise two sets of alleles, one set of which will comprise the same alleles as the homozygous alleles of inbred line PHDWA.

PLANT. As used herein, the term “plant” includes reference to an immature or mature whole plant, including a plant that has been detasseled or from which seed or grain has been removed. Seed or embryo that will produce the plant is also considered to be the plant.

PLANT PARTS. As used herein, the term “plant parts” includes leaves, stems, roots, seed, grain, embryo, pollen, ovules, flowers, ears, cobs, husks, stalks, root tips, anthers, pericarp, silk, tissue, cells and the like.

PLTHT=PLANT HEIGHT. This is a measure of the height of the plant from the ground to the tip of the tassel in centimeters.

POLSC=POLLEN SCORE. A 1 to 9 visual rating indicating the amount of pollen shed. The higher the score the more pollen shed.

POLWT=POLLEN WEIGHT. This is calculated by dry weight of tassels collected as shedding commences minus dry weight from similar tassels harvested after shedding is complete.

POP K/A=PLANT POPULATIONS. Measured as 1000s per acre.

POP ADV=PLANT POPULATION ADVANTAGE. The plant population advantage of variety #1 over variety #2 as calculated by PLANT POPULATION of variety #2−PLANT POPULATION of variety #1=PLANT POPULATION ADVANTAGE of variety #1.

PRM=PREDICTED RELATIVE MATURITY. This trait, predicted relative maturity, is based on the harvest moisture of the grain. The relative maturity rating is based on a known set of checks and utilizes standard linear regression analyses and is also referred to as the Comparative Relative Maturity Rating System that is similar to the Minnesota Relative Maturity Rating System.

PRMSHD=A relative measure of the growing degree units (GDU) required to reach 50% pollen shed. Relative values are predicted values from the linear regression of observed GDU's on relative maturity of commercial checks.

PROT=GRAIN PROTEIN. Absolute value of protein content of the kernel as predicted by Near-infrared Transmittance and expressed as a percent of dry matter.

RESISTANCE. Synonymous with tolerance. The ability of a plant to withstand exposure to an insect, disease, herbicide or other condition. A resistant plant variety will have a level of resistance higher than a comparable wild-type variety.

RTLDG=ROOT LODGING. Root lodging is the percentage of plants that do not root lodge; plants that lean from the vertical axis at an approximately 30 degree angle or greater would be counted as root lodged. Data are collected only when sufficient selection pressure exists in the experiment measured.

RTLADV=ROOT LODGING ADVANTAGE. The root lodging advantage of variety #1 over variety #2. Data are collected only when sufficient selection pressure exists in the experiment measured.

SCTGRN=SCATTER GRAIN. A 1 to 9 visual rating indicating the amount of scatter grain (lack of pollination or kernel abortion) on the ear. The higher the score the less scatter grain.

SDGVGR=SEEDLING VIGOR. This is the visual rating (1 to 9) of the amount of vegetative growth after emergence at the seedling stage (approximately five leaves). A higher score indicates better vigor.

SEL IND=SELECTION INDEX. The selection index gives a single measure of the hybrid's worth based on information for up to five traits. A maize breeder may utilize his or her own set of traits for the selection index. One of the traits that is almost always included is yield. The selection index data presented in the tables represent the mean value averaged across testing stations.

SELF POLLINATION. A plant is self-pollinated if pollen from one flower is transferred to the same or another flower of the same plant.

SIB POLLINATION. A plant is sib-pollinated when individuals within the same family or line are used for pollination.

SINGLE LOCUS CONVERSION TRAIT. A trait that can be introgressed into a corn line through introgression and/or transformation of a single locus. Examples of such single locus traits include mutant genes, transgenes and native traits finely mapped to a single locus. One or more single locus conversion traits may be introduced into a single corn line.

SLFBLT=SOUTHERN LEAF BLIGHT (Helminthosporium maydis or Bipolaris maydis). A 1 to 9 visual rating indicating the resistance to Southern Leaf Blight. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

SOURST=SOUTHERN RUST (Puccinia polysora). A 1 to 9 visual rating indicating the resistance to Southern Rust. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

STAGRN=STAY GREEN. Stay green is the measure of plant health near the time of black layer formation (physiological maturity). A high score indicates better late-season plant health.

STDADV=STALK STANDING ADVANTAGE. The advantage of variety #1 over variety #2 for the trait STK CNT.

STKCNT=NUMBER OF PLANTS. This is the final stand or number of plants per plot.

STKLDG=STALK LODGING REGULAR. This is the percentage of plants that did not stalk lodge (stalk breakage) at regular harvest (when grain moisture is between about 20 and 30%) as measured by either natural lodging or pushing the stalks and determining the percentage of plants that break below the ear. Data are collected only when sufficient selection pressure exists in the experiment measured.

STKLDS=STALK LODGING SCORE. A plant is considered as stalk lodged if the stalk is broken or crimped between the ear and the ground. This can be caused by any or a combination of the following: strong winds late in the season, disease pressure within the stalks, ECB damage or genetically weak stalks. This trait should be taken just prior to or at harvest. Expressed on a 1 to 9 scale with 9 being no lodging. Data are collected only when sufficient selection pressure exists in the experiment measured.

STLLPN=LATE STALK LODGING. This is the percent of plants that did not stalk lodge (stalk breakage or crimping) at or around late season harvest (when grain moisture is below 20%) as measured by either natural lodging or pushing the stalks and determining the percentage of plants that break or crimp below the ear. Data are collected only when sufficient selection pressure exists in the experiment measured.

STLPCN=STALK LODGING REGULAR. This is an estimate of the percentage of plants that did not stalk lodge (stalk breakage) at regular harvest (when grain moisture is between about 20 and 30%) as measured by either natural lodging or pushing the stalks and determining the percentage of plants that break below the ear. Data are collected only when sufficient selection pressure exists in the experiment measured.

STRT=GRAIN STARCH. Absolute value of starch content of the kernel as predicted by Near-infrared Transmittance and expressed as a percent of dry matter.

STWWLT=Stewart's Wilt (Erwinia stewartii). A 1 to 9 visual rating indicating the resistance to Stewart's Wilt. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

TASBLS=TASSEL BLAST. A 1 to 9 visual rating was used to measure the degree of blasting (necrosis due to heat stress) of the tassel at the time of flowering. A 1 would indicate a very high level of blasting at time of flowering, while a 9 would have no tassel blasting. Data are collected only when sufficient selection pressure exists in the experiment measured.

TASSZ=TASSEL SIZE. A 1 to 9 visual rating was used to indicate the relative size of the tassel. The higher the rating the larger the tassel.

TAS WT=TASSEL WEIGHT. This is the average weight of a tassel (grams) just prior to pollen shed.

TEXEAR=EAR TEXTURE. A 1 to 9 visual rating was used to indicate the relative hardness (smoothness of crown) of mature grain. A 1 would be very soft (extreme dent) while a 9 would be very hard (flinty or very smooth crown).

TILLER=TILLERS. A count of the number of tillers per plot that could possibly shed pollen was taken. Data are given as a percentage of tillers: number of tillers per plot divided by number of plants per plot.

TSTWT=TEST WEIGHT (UNADJUSTED). The measure of the weight of the grain in pounds for a given volume (bushel).

TSWADV=TEST WEIGHT ADVANTAGE. The test weight advantage of variety #1 over variety #2.

WIN M %=PERCENT MOISTURE WINS.

WIN Y %=PERCENT YIELD WINS.

YIELD BU/A=YIELD (BUSHELS/ACRE). Yield of the grain at harvest by weight or volume (bushels) per unit area (acre) adjusted to 15% moisture.

YLDADV=YIELD ADVANTAGE. The yield advantage of variety #1 over variety #2 as calculated by: YIELD of variety #1−YIELD variety #2=YIELD ADVANTAGE of variety #1.

YLDSC=YIELD SCORE. A 1 to 9 visual rating was used to give a relative rating for yield based on plot ear piles. The higher the rating the greater visual yield appearance.

Definitions for Area of Adaptability

When referring to area of adaptability, such term is used to describe the location with the environmental conditions that would be well suited for this maize line. Area of adaptability is based on a number of factors, for example: days to maturity, insect resistance, disease resistance, and drought resistance. Area of adaptability does not indicate that the maize line will grow in every location within the area of adaptability or that it will not grow outside the area.

-   Central Corn Belt: Iowa, Illinois, Indiana -   Drylands: non-irrigated areas of North Dakota, South Dakota,     Nebraska, Kansas, Colorado, and Oklahoma -   Eastern U.S.: Ohio, Pennsylvania, Delaware, Maryland, Virginia, and     West Virginia -   North central U.S.: Minnesota and Wisconsin -   Northeast: Michigan, New York, Vermont, and Ontario and Quebec     Canada -   Northwest U.S.: North Dakota, South Dakota, Wyoming, Washington,     Oregon, Montana, Utah, and Idaho -   South central U.S.: Missouri, Tennessee, Kentucky, Arkansas -   Southeast U.S.: North Carolina, South Carolina, Georgia, Florida,     Alabama, Mississippi, and Louisiana -   Southwest U.S.: Texas, Oklahoma, New Mexico, Arizona -   Western U.S.: Nebraska, Kansas, Colorado, and California -   Maritime Europe Northern France, Germany, Belgium, Netherlands and     Austria

DETAILED DESCRIPTION OF THE INVENTION AND FURTHER EMBODIMENTS

All tables discussed in the Detailed Description of the Invention and Further Embodiments section can found at the end of the section.

Morphological and Physiological Characteristics of PHDWA

Inbred maize line PHDWA is a yellow flint maize inbred that may be used as either a male or female in the production of the first generation F1 maize hybrid although PHDWA may be best suited for use as a male. Inbred maize line PHDWA is best adapted to the Central and Southcentral corn belt in the U.S. and can be used to produce hybrids in the 110 to 116 RM range. Inbred maize line PHDWA demonstrates below average yield, above average Grey Leaf Spot and Fusarium ear rot resistance. Inbred maize line PHDWA has below average pollen shed and plant height. In hybrid combination, inbred PHDWA demonstrates average yield, below average plant and ear heights and very good resistance to root lodging.

The inbred has shown uniformity and stability within the limits of environmental influence for all the traits as described in the Variety Description Information (Table 1, found at the end of the section). The inbred has been self-pollinated and ear-rowed a sufficient number of generations with careful attention paid to uniformity of plant type to ensure the homozygosity and phenotypic stability necessary for use in commercial hybrid seed production. The line has been increased both by hand and in isolated fields with continued observation for uniformity. No variant traits have been observed or are expected in PHDWA.

Inbred maize line PHDWA, being substantially homozygous, can be reproduced by planting seeds of the line, growing the resulting maize plants under self-pollinating or sib-pollinating conditions with adequate isolation, and harvesting the resulting seed using techniques familiar to the agricultural arts.

Genotypic Characteristics of PHDWA

In addition to phenotypic observations, a plant can also be identified by its genotype. The genotype of a plant can be characterized through a genetic marker profile, which can identify plants of the same variety or a related variety, or be used to determine or validate a pedigree. The SSR profile of Inbred PHDWA can be found in Table 2 at the end of this section. As a result of inbreeding, PHDWA is substantially homozygous. This homozygosity has been characterized at the loci shown in the marker profile provided herein. An F1 hybrid made with PHDWA would comprise the marker profile of PHDWA shown herein. This is because an F1 hybrid is the sum of its inbred parents, e.g., if one inbred parent is homozygous for allele x at a particular locus, and the other inbred parent is homozygous for allele y at that locus, the F1 hybrid will be x.y (heterozygous) at that locus. The profile can therefore be used to identify hybrids comprising PHDWA as a parent, since such hybrids will comprise two sets of alleles, one set of which will be from PHDWA. The determination of the male set of alleles and the female set of alleles may be made by profiling the hybrid and the pericarp of the hybrid seed, which is composed of maternal parent cells. One way to obtain the paternal parent profile is to subtract the pericarp profile from the hybrid profile.

Subsequent generations of progeny produced by selection and breeding are expected to be of genotype x (homozygous), y (homozygous), or x.y (heterozygous) for these locus positions. When the F1 plant is used to produce an inbred, the resulting inbred should be either x or y for that allele. In that regard, a unique allele or combination of alleles unique to that inbred can be used to identify progeny plants that retain those unique alleles or combinations of alleles.

Therefore, in accordance with the above, an embodiment of this invention is a PHDWA progeny maize plant or plant part that is a first generation (F1) hybrid maize plant comprising two sets of alleles, wherein one set of the alleles is the same as PHDWA at all of the SSR loci listed in Table 2. A maize cell wherein one set of the alleles is the same as PHDWA at all of the SSR loci listed in Table 2 is also an embodiment of the invention. This maize cell may be a part of a hybrid seed, plant or plant part produced by crossing PHDWA with another inbred maize plant.

Genetic marker profiles can be obtained by techniques such as Restriction Fragment Length Polymorphisms (RFLPs), Randomly Amplified Polymorphic DNAs (RAPDs), Arbitrarily Primed Polymerase Chain Reaction (AP-PCR), DNA Amplification Fingerprinting (DAF), Sequence Characterized Amplified Regions (SCARs), Amplified Fragment Length Polymorphisms (AFLPs), Simple Sequence Repeats (SSRs) which are also referred to as Microsatellites, and Single Nucleotide Polymorphisms (SNPs). For example, see Berry, Don et al., “Assessing Probability of Ancestry Using Simple Sequence Repeat Profiles: Applications to Maize Hybrids and Inbreds”, Genetics, 2002, 161:813-824, and Berry, Don et al., “Assessing Probability of Ancestry Using Simple Sequence Repeat Profiles: Applications to Maize Inbred Lines and Soybean Varieties”, Genetics, 2003, 165: 331-342.

Particular markers used for these purposes are not limited to the set of markers disclosed herein, but may include any type of marker and marker profile which provides a means of distinguishing varieties. In addition to being used for identification of Inbred maize line PHDWA, a hybrid produced through the use of PHDWA, and the identification or verification of pedigree for progeny plants produced through the use of PHDWA, the genetic marker profile is also useful in further breeding and in developing an introgressed trait conversion of PHDWA.

Means of performing genetic marker profiles using SSR polymorphisms are well known in the art. SSRs are genetic markers based on polymorphisms in repeated nucleotide sequences, such as microsatellites. A marker system based on SSRs can be highly informative in linkage analysis relative to other marker systems in that multiple alleles may be present. Another advantage of this type of marker is that, through use of flanking primers, detection of SSRs can be achieved, for example, by the polymerase chain reaction (PCR), thereby eliminating the need for labor-intensive Southern hybridization. The PCR detection is done by use of two oligonucleotide primers flanking the polymorphic segment of repetitive DNA. Repeated cycles of heat denaturation of the DNA followed by annealing of the primers to their complementary sequences at low temperatures, and extension of the annealed primers with DNA polymerase, comprise the major part of the methodology.

Following amplification, markers can be scored by electrophoresis of the amplification products. Scoring of marker genotype is based on the size of the amplified fragment, which may be measured by the number of base pairs of the fragment. While variation in the primer used or in laboratory procedures can affect the reported fragment size, relative values should remain constant regardless of the specific primer or laboratory used. When comparing lines it is preferable if all SSR profiles are performed in the same lab. The SSR analyses reported herein were conducted in-house at Pioneer Hi-Bred. An SSR service is available to the public on a contractual basis by DNA Landmarks in Saint-Jean-sur-Richelieu, Quebec, Canada.

Primers used for the SSRs reported herein are publicly available and may be found in the Maize GDB on the World Wide Web at maizegdb.org (sponsored by the USDA Agricultural Research Service), in Sharopova et al. (Plant Mol. Biol. 48(5-6):463-481), Lee et al. (Plant Mol. Biol. 48(5-6); 453-461), or may be constructed from sequences if reported herein. Primers may be constructed from publicly available sequence information. Some marker information may also be available from DNA Landmarks.

Map information is provided by bin number as reported in the Maize GDB for the IBM 2 and/or IBM 2 Neighbors maps. The bin number digits to the left of decimal point represent the chromosome on which such marker is located, and the digits to the right of the decimal represent the location on such chromosome. A bin number.xx designation indicates that the bin location on that chromosome is not known. Map positions are also available on the Maize GDB for a variety of different mapping populations.

PHDWA and its plant parts can be identified through a molecular marker profile. An inbred corn plant cell having the SSR genetic marker profile shown in Table 2 is an embodiment of the invention. Such plant cell may be either diploid or haploid.

Also encompassed within the scope of the invention are plants and plant parts substantially benefiting from the use of PHDWA in their development, such as PHDWA comprising a introgressed trait through backcross conversion or transformation, and which may be identified by having an SSR molecular marker profile with a high percent identity to PHDWA, such as at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5% identity. Likewise, percent similarity at these percentages may be used to identify hybrid and other non-inbred plants produced by the use of PHDWA.

An embodiment of this invention is an inbred PHDWA progeny maize plant or plant part comprising the same homozygous alleles as the plant or plant part of PHDWA for at least 90% of the SSR loci listed in Table 2. A plant cell comprising the same homozygous alleles as a plant cell of PHDWA for at least 90% of the SSR loci listed in Table 2 is also an embodiment of this invention. In these specific embodiments, 90% may also be replaced by any integer or partial integer percent of 80% or greater as listed above. One means of producing such a progeny plant, plant part or cell is through the backcrossing and/or transformation methods described herein.

Similarly, an embodiment of this invention is a PHDWA progeny maize plant or plant part comprising at least one allele per locus that is the same allele as the plant or plant part of PHDWA for at least 90% of the SSR loci listed in Table 2. This progeny plant may be a hybrid. A progeny or hybrid plant cell wherein at least one allele per locus that is the same allele as the plant cell PHDWA for at least 90% of the SSR loci listed in Table 2 is also a specific embodiment of this invention. In these specific embodiments, 90% may also be replaced by any integer percent listed above. One means of producing such a progeny or hybrid plant, plant part or cell is through the backcrossing and/or transformation methods described herein.

In addition, the SSR profile of PHDWA also can be used to identify essentially derived varieties and other progeny lines developed from the use of PHDWA, as well as cells and other plant parts thereof. Progeny plants and plant parts produced using PHDWA may be identified by having a molecular marker profile of at least 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5% genetic contribution from inbred line PHDWA, as measured by either percent identity or percent similarity.

Comparing PHDWA to Other Inbreds

A breeder uses various methods to help determine which plants should be selected from segregating populations and ultimately which inbred lines will be used to develop hybrids for commercialization. In addition to knowledge of the germplasm and plant genetics, a part of the selection process is dependent on experimental design coupled with the use of statistical analysis. Experimental design and statistical analysis are used to help determine which plants, which family of plants, and finally which inbred lines and hybrid combinations are significantly better or different for one or more traits of interest. Experimental design methods are used to assess error so that differences between two inbred lines or two hybrid lines can be more accurately evaluated. Statistical analysis includes the calculation of mean values, determination of the statistical significance of the sources of variation, and the calculation of the appropriate variance components. Either a five or a one percent significance level is customarily used to determine whether a difference that occurs for a given trait is real or due to the environment or experimental error. One of ordinary skill in the art of plant breeding would know how to evaluate the traits of two plant varieties to determine if there is no significant difference between the two traits expressed by those varieties. For example, see Fehr, Walt, Principles of Cultivar Development, p. 261-286 (1987). Mean trait values may be used to determine whether trait differences are significant. Trait values should preferably be measured on plants grown under the same environmental conditions, and environmental conditions should be appropriate for the traits or traits being evaluated. Sufficient selection pressure should be present for optimum measurement of traits of interest such as herbicide, insect or disease resistance. Similarly, an introgressed trait conversion of PHDWA for resistance, such as herbicide resistance, should not be compared to PHDWA in the presence of the herbicide when comparing non-resistance related traits such as plant height and yield.

In Table 3, data from traits and characteristics of inbred maize line PHDWA per se are given and compared to other maize inbred lines and hybrids. The following are the results of these comparisons. The results in Table 3 show inbred PHDWA has significantly different traits compared to other maize inbred lines.

The results in Table 3A compare inbred PHDWA to inbred PH581. The results show inbred PHDWA has significantly different plant height, ear height and number of growing degree units for 50% of the plants to be shedding pollen compared to PH581.

The results in Table 3B compare inbred PHDWA to inbred PH1BC. The results show inbred PHDWA differs significantly over multiple traits including number of growing degree units for 50% of the plants to be shedding pollen, pollen weight, tassel size, plant height and ear height when compared to inbred PH1BC.

Development of Maize Hybrids Using PHDWA

A single cross maize hybrid results from the cross of two inbred lines, each of which has a genotype that complements the genotype of the other. The hybrid progeny of the first generation is designated F1. In the development of commercial hybrids in a maize plant breeding program, only the F1 hybrid plants are sought. F1 hybrids are more vigorous than their inbred parents. This hybrid vigor, or heterosis, can be manifested in many polygenic traits, including increased vegetative growth and increased yield.

PHDWA may be used to produce hybrid maize. One such embodiment is the method of crossing inbred maize line PHDWA with another maize plant, such as a different maize inbred line, to form a first generation F1 hybrid seed. The first generation F1 hybrid seed, plant and plant part produced by this method is an embodiment of the invention. The first generation F1 seed, plant and plant part will comprise an essentially complete set of the alleles of inbred line PHDWA. One of ordinary skill in the art can utilize either breeder books or molecular methods to identify a particular F1 hybrid plant produced using inbred line PHDWA. Further, one of ordinary skill in the art may also produce F1 hybrids with transgenic, male sterile and/or backcross conversions of inbred line PHDWA

The development of a maize hybrid in a maize plant breeding program involves three steps: (1) the selection of plants from various germplasm pools for initial breeding crosses; (2) the selfing of the selected plants from the breeding crosses for several generations to produce a series of inbred lines, such as PHDWA, which, although different from each other, breed true and are highly uniform; and (3) crossing the selected inbred lines with different inbred lines to produce the hybrids. During the inbreeding process in maize, the vigor of the lines decreases, and so one would not be likely to use PHDWA directly to produce grain. However, vigor is restored when PHDWA is crossed to a different inbred line to produce a commercial F1 hybrid. An important consequence of the homozygosity and homogeneity of the inbred line is that the hybrid between a defined pair of inbreds may be reproduced indefinitely as long as the homogeneity of the inbred parents is maintained.

PHDWA may be used to produce a single cross hybrid, a double cross hybrid, or a three-way hybrid. A single cross hybrid is produced when two inbred lines are crossed to produce the F1 progeny. A double cross hybrid is produced from four inbred lines crossed in pairs (A×B and C×D) and then the two F1 hybrids are crossed again (A×B)×(C×D). A three-way cross hybrid is produced from three inbred lines where two of the inbred lines are crossed (A×B) and then the resulting F1 hybrid is crossed with the third inbred (A×B)×C. In each case, pericarp tissue from the female parent will be a part of and protect the hybrid seed.

Combining Ability of PHDWA

Combining ability of a line, as well as the performance of the line per se, is a factor in the selection of improved maize inbreds. Combining ability refers to a line's contribution as a parent when crossed with other lines to form hybrids. The hybrids formed for the purpose of selecting superior lines may be referred to as test crosses, and include comparisons to other hybrid varieties grown in the same environment (same cross, location and time of planting). One way of measuring combining ability is by using values based in part on the overall mean of a number of test crosses weighted by number of experiment and location combinations in which the hybrid combinations occurs. The mean may be adjusted to remove environmental effects and known genetic relationships among the lines.

General combining ability provides an overall score for the inbred over a large number of test crosses. Specific combining ability provides information on hybrid combinations formed by PHDWA and a specific inbred parent. A line such as PHDWA which exhibits good general combining ability may be used in a large number of hybrid combinations.

A general combining ability report for inbred PHDWA is provided in Table 4. This data represents the overall mean value for these traits over hundreds of test crosses. Table 4 demonstrates that inbred PHDWA shows good general combining ability for hybrid production.

Hybrid Comparisons

These hybrid comparisons represent specific hybrid crosses with PHDWA and a comparison of these specific hybrids with other hybrids with favorable characteristics. These comparisons illustrate the good specific combining ability of PHDWA.

The results in Table 5A and Table 5B compare a specific hybrid for which inbred PHDWA is a parent with other hybrids. The results show that inbred PHDWA shows good specific combining ability.

The data in Table 6 show that numerous species of the genus of F1 hybrids created with PHDWA have been reduced to practice. Phenotypic data are presented for these hybrids and are based on replicated field trials. Of course, many more species of this genus may be created by one of ordinary skill in the art without undue experimentation by crossing PHDWA with a multitude of publicly available inbred lines. For example, see J. T. Gerdes et al., Compilation of North American Maize Breeding Germplasm, pp. 1-87 (Crop Science Society of America, 1993) which is incorporated by reference for this purpose.

Introgression of a New Locus or Trait into PHDWA

PHDWA represents a new base genetic line into which a new locus or trait may be introgressed. Direct transformation and backcrossing represent two important methods that can be used to accomplish such an introgression. The term backcross conversion and single locus conversion are used interchangeably to designate the product of a backcrossing program.

Backcross Conversions of PHDWA

A backcross conversion of PHDWA occurs when DNA sequences are introduced through backcrossing (Hallauer et al. in Corn and Corn Improvement, Sprague and Dudley, Third Ed. 1998), with PHDWA utilized as the recurrent parent. Both naturally occurring and transgenic DNA sequences may be introduced through backcrossing techniques. A backcross conversion may produce a plant with a trait or locus conversion in at least one or more backcrosses, including at least 2 crosses, at least 3 crosses, at least 4 crosses, at least 5 crosses and the like. Molecular marker assisted breeding or selection may be utilized to reduce the number of backcrosses necessary to achieve the backcross conversion. For example, see Openshaw, S. J. et al., Marker-assisted Selection in Backcross Breeding, In: Proceedings Symposium of the Analysis of Molecular Data, August 1994, Crop Science Society of America, Corvallis, Oreg., where it is demonstrated that a backcross conversion can be made in as few as two backcrosses.

The complexity of the backcross conversion method depends on the type of trait being transferred (single genes or closely linked genes as vs. unlinked genes), the level of expression of the trait, the type of inheritance (cytoplasmic or nuclear) and the types of parents included in the cross. It is understood by those of ordinary skill in the art that for single gene traits that are relatively easy to classify, the backcross method is effective and relatively easy to manage. (See Hallauer et al. in Corn and Corn Improvement, Sprague and Dudley, Third Ed. 1998). Desired traits that may be transferred through backcross conversion include, but are not limited to, waxy starch, sterility (nuclear and cytoplasmic), fertility restoration, grain color (white), nutritional enhancements, drought resistance, enhanced nitrogen utilization efficiency, altered nitrogen responsiveness, altered fatty acid profile, increased digestibility, low phytate, industrial enhancements, disease resistance (bacterial, fungal or viral), insect resistance, herbicide resistance and yield enhancements. In addition, an introgression site itself, such as an FRT site, Lox site or other site specific integration site, may be inserted by backcrossing and utilized for direct insertion of one or more genes of interest into a specific plant variety. In some embodiments of the invention, the number of loci that may be backcrossed into PHDWA is at least 1, 2, 3, 4, or 5 and/or no more than 6, 5, 4, 3, or 2. A single loci may contain several transgenes, such as a transgene for disease resistance that, in the same expression vector, also contains a transgene for herbicide resistance. The gene for herbicide resistance may be used as a selectable marker and/or as a phenotypic trait. A single locus conversion of site specific integration system allows for the integration of multiple genes at the converted loci. Further, SSI and FRT technologies known to those of skill in the art in the art may result in multiple gene introgressions at a single locus.

The backcross conversion may result from either the transfer of a dominant allele or a recessive allele. Selection of progeny containing the trait of interest is accomplished by direct selection for a trait associated with a dominant allele. Transgenes transferred via backcrossing typically function as a dominant single gene trait and are relatively easy to classify. Selection of progeny for a trait that is transferred via a recessive allele, such as the waxy starch characteristic, requires growing and selfing the first backcross generation to determine which plants carry the recessive alleles. Recessive traits may require additional progeny testing in successive backcross generations to determine the presence of the locus of interest. The last backcross generation is usually selfed to give pure breeding progeny for the gene(s) being transferred, although a backcross conversion with a stably introgressed trait may also be maintained by further backcrossing to the recurrent parent with selection for the converted trait.

Along with selection for the trait of interest, progeny are selected for the phenotype of the recurrent parent. While occasionally additional polynucleotide sequences or genes may be transferred along with the backcross conversion, the backcross conversion line “fits into the same hybrid combination as the recurrent parent inbred line and contributes the effect of the additional gene added through the backcross.” Poehlman et al. (1995, page 334). It has been proposed that in general there should be at least four backcrosses when it is important that the recovered lines be essentially identical to the recurrent parent except for the characteristic being transferred (Fehr 1987, Principles of Cultivar Development). However, as noted above, the number of backcrosses necessary can be reduced with the use of molecular markers. Other factors, such as a genetically similar donor parent, may also reduce the number of backcrosses necessary.

One process for adding or modifying a trait or locus in maize inbred line PHDWA comprises crossing PHDWA plants grown from PHDWA seed with plants of another maize line that comprise the desired trait or locus, selecting F1 progeny plants that comprise the desired trait or locus to produce selected F1 progeny plants, crossing the selected progeny plants with the PHDWA plants to produce backcross progeny plants, selecting for backcross progeny plants that have the desired trait or locus and the morphological characteristics of maize inbred line PHDWA to produce selected backcross progeny plants; and backcrossing to PHDWA three or more times in succession to produce selected fourth or higher backcross progeny plants that comprise said trait or locus. The modified PHDWA may be further characterized as having the physiological and morphological characteristics of maize inbred line PHDWA listed in Table 1 as determined at the 5% significance level when grown in the same environmental conditions and/or may be characterized by percent similarity or identity to PHDWA as determined by SSR markers. The above method may be utilized with fewer backcrosses in appropriate situations, such as when the donor parent is highly related or markers are used in the selection step. Desired traits that may be used include those nucleic acids known in the art, some of which are listed herein, that will affect traits through nucleic acid expression or inhibition. Desired loci include the introgression of FRT, Lox and other sites for site specific integration.

In addition, the above process and other similar processes described herein may be used to produce F1 hybrid maize seed by adding a step at the end of the process that comprises crossing PHDWA with the introgressed trait or locus with a different maize plant and harvesting the resultant F1 hybrid maize seed.

Male Sterility and Hybrid Seed Production

Hybrid seed production requires elimination or inactivation of pollen produced by the female inbred parent. Incomplete removal or inactivation of the pollen provides the potential for self-pollination. A reliable method of controlling male fertility in plants offers the opportunity for improved seed production.

PHDWA can be produced in a male-sterile form. There are several ways in which a maize plant can be manipulated so that it is male sterile. These include use of manual or mechanical emasculation (or detasseling), use of one or more genetic factors that confer male sterility, including cytoplasmic genetic and/or nuclear genetic male sterility, use of gametocides and the like. A male sterile inbred designated PHDWA may include one or more genetic factors, which result in cytoplasmic genetic and/or nuclear genetic male sterility. All of such embodiments are within the scope of the present claims. The male sterility may be either partial or complete male sterility.

Hybrid maize seed is often produced by a male sterility system incorporating manual or mechanical detasseling. Alternate strips of two maize inbreds are planted in a field, and the pollen-bearing tassels are removed from one of the inbreds (female). Provided that there is sufficient isolation from sources of foreign maize pollen, the ears of the detasseled inbred will be fertilized only from the other inbred (male), and the resulting seed is therefore hybrid and will form hybrid plants.

The laborious detasseling process can be avoided by using cytoplasmic male-sterile (CMS) inbreds. Plants of a CMS inbred are male sterile as a result of genetic factors in the cytoplasm, as opposed to the nucleus, and so nuclear linked genes are not transferred during backcrossing. Thus, this characteristic is inherited exclusively through the female parent in maize plants, since only the female provides cytoplasm to the fertilized seed. CMS plants are fertilized with pollen from another inbred that is not male-sterile. Pollen from the second inbred may or may not contribute genes that make the hybrid plants male-fertile, and either option may be preferred depending on the intended use of the hybrid. The same hybrid seed, a portion produced from detasseled fertile maize and a portion produced using the CMS system, can be blended to insure that adequate pollen loads are available for fertilization when the hybrid plants are grown. CMS systems have been successfully used since the 1950's, and the male sterility trait is routinely backcrossed into inbred lines. See Wych, p. 585-586, 1998.

There are several methods of conferring genetic male sterility available, such as multiple mutant genes at separate locations within the genome that confer male sterility, as disclosed in U.S. Pat. Nos. 4,654,465 and 4,727,219 to Brar et al. and chromosomal translocations as described by Patterson in U.S. Pat. Nos. 3,861,709 and 3,710,511. In addition to these methods, Albertsen et al., U.S. Pat. No. 5,432,068, describe a system of nuclear male sterility which includes: identifying a gene which is critical to male fertility; silencing this native gene which is critical to male fertility; removing the native promoter from the essential male fertility gene and replacing it with an inducible promoter; inserting this genetically engineered gene back into the plant; and thus creating a plant that is male sterile because the inducible promoter is not “on” resulting in the male fertility gene not being transcribed. Fertility is restored by inducing, or turning “on”, the promoter, which in turn allows the gene that confers male fertility to be transcribed.

These, and the other methods of conferring genetic male sterility in the art, each possess their own benefits and drawbacks. Some other methods use a variety of approaches such as delivering into the plant a gene encoding a cytotoxic substance associated with a male tissue specific promoter or an antisense system in which a gene critical to fertility is identified and an antisense to that gene is inserted in the plant (see Fabinjanski, et al. EPO 89/3010153.8 publication no. 329,308 and PCT application PCT/CA90/00037 published as WO 90/08828).

Another system for controlling male sterility makes use of gametocides. Gametocides are not a genetic system, but rather a topical application of chemicals. These chemicals affect cells that are critical to male fertility. The application of these chemicals affects fertility in the plants only for the growing season in which the gametocide is applied (see Carlson, Glenn R., U.S. Pat. No.: 4,936,904). Application of the gametocide, timing of the application and genotype specificity often limit the usefulness of the approach and it is not appropriate in all situations.

Incomplete control over male fertility may result in self-pollinated seed being unintentionally harvested and packaged with hybrid seed. This would typically be only female parent seed, because the male plant is grown in rows that are typically destroyed prior to seed development. Once the seed from the hybrid bag is planted, it is possible to identify and select these self-pollinated plants. These self-pollinated plants will be one of the inbred lines used to produce the hybrid. Though the possibility of inbred PHDWA being included in a hybrid seed bag exists, the occurrence is very low because much care is taken by seed companies to avoid such inclusions. It is worth noting that hybrid seed is sold to growers for the production of grain or forage and not for breeding or seed production. These self-pollinated plants can be identified and selected by one skilled in the art due to their less vigorous appearance for vegetative and/or reproductive characteristics, including shorter plant height, small ear size, ear and kernel shape, cob color, or other characteristics.

Identification of these self-pollinated lines can also be accomplished through molecular marker analyses. See, “The Identification of Female Selfs in Hybrid Maize: A Comparison Using Electrophoresis and Morphology”, Smith, J. S. C. and Wych, R. D., Seed Science and Technology 14, 1-8 (1995), the disclosure of which is expressly incorporated herein by reference. Through these technologies, the homozygosity of the self pollinated line can be verified by analyzing allelic composition at various loci along the genome. Those methods allow for rapid identification of the invention disclosed herein. See also, “Identification of Atypical Plants in Hybrid Maize Seed by Postcontrol and Electrophoresis” Sarca, V. et al., Probleme de Genetica Teoritica si Aplicata Vol. 20 (1) p. 29-42.

An embodiment of this invention is a process for producing seed of PHDWA comprising planting a collection of seed comprising seed of a hybrid, one of whose parents is inbred PHDWA said collection also comprising seed of said inbred, growing plants from said collection of seed, identifying inbred parent plants, selecting said inbred parent plant; and controlling pollination to preserve the homozygosity of said inbred parent plant.

Transformation

The advent of new molecular biological techniques has allowed the isolation and characterization of genetic elements with specific functions, such as encoding specific protein products. Scientists in the field of plant biology developed a strong interest in engineering the genome of plants to contain and express foreign genetic elements, or additional, or modified versions of native or endogenous genetic elements in order to alter the traits of a plant in a specific manner. Any DNA sequences, whether from a different species or from the same species, which are inserted into the genome using transformation are referred to herein collectively as “transgenes”. In some embodiments of the invention, a transformed variant of PHDWA may contain at least one transgene but could contain at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 and/or no more than 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, or 2. Over the last fifteen to twenty years several methods for producing transgenic plants have been developed, and the present invention also relates to transformed versions of the claimed inbred maize line PHDWA as well as hybrid combinations thereof.

Numerous methods for plant transformation have been developed, including biological and physical plant transformation protocols. See, for example, Miki et al., “Procedures for Introducing Foreign DNA into Plants” in Methods in Plant Molecular Biology and Biotechnology, Glick, B. R. and Thompson, J. E. Eds. (CRC Press, Inc., Boca Raton, 1993) pages 67-88 and Armstrong, “The First Decade of Maize Transformation: A Review and Future Perspective” (Maydica 44:101-109, 1999). In addition, expression vectors and in vitro culture methods for plant cell or tissue transformation and regeneration of plants are available. See, for example, Gruber et al., “Vectors for Plant Transformation” in Methods in Plant Molecular Biology and Biotechnology, Glick, B. R. and Thompson, J. E. Eds. (CRC Press, Inc., Boca Raton, 1993) pages 89-119.

The most prevalent types of plant transformation involve the construction of an expression vector. Such a vector comprises a DNA sequence that contains a gene under the control of or operatively linked to a regulatory element, for example a promoter. The vector may contain one or more genes and one or more regulatory elements.

A genetic trait which has been engineered into the genome of a particular maize plant using transformation techniques, could be moved into the genome of another line using traditional breeding techniques that are well known in the plant breeding arts. For example, a backcrossing approach is commonly used to move a transgene from a transformed maize plant to an elite inbred line, and the resulting progeny would then comprise the transgene(s). Also, if an inbred line was used for the transformation then the transgenic plants could be crossed to a different inbred in order to produce a transgenic hybrid maize plant.

Various genetic elements can be introduced into the plant genome using transformation. These elements include, but are not limited to genes; coding sequences; inducible, constitutive, and tissue specific promoters; enhancing sequences; and signal and targeting sequences. For example, see the traits, genes and transformation methods listed in U.S. Pat. Nos. 6,118,055 and 6,284,953, which are herein incorporated by reference. In addition, transformability of a line can be increased by introgressing the trait of high transformability from another line known to have high transformability, such as Hi-II. See U.S. Patent Application Publication US2004/0016030 (2004).

With transgenic plants according to the present invention, a foreign protein can be produced in commercial quantities. Thus, techniques for the selection and propagation of transformed plants, which are well understood in the art, yield a plurality of transgenic plants that are harvested in a conventional manner, and a foreign protein then can be extracted from a tissue of interest or from total biomass. Protein extraction from plant biomass can be accomplished by known methods which are discussed, for example, by Heney and Orr, Anal. Biochem. 114: 92-6 (1981).

A genetic map can be generated, primarily via conventional Restriction Fragment Length Polymorphisms (RFLP), Polymerase Chain Reaction (PCR) analysis, Simple Sequence Repeats (SSR) and Single Nucleotide Polymorphisms (SNP) that identifies the approximate chromosomal location of the integrated DNA molecule. For exemplary methodologies in this regard, see Glick and Thompson, Methods in Plant Molecular Biology and Biotechnology 269-284 (CRC Press, Boca Raton, 1993).

Wang et al. discuss “Large Scale Identification, Mapping and Genotyping of Single-Nucleotide Polymorphisms in the Human Genome”, Science, 280:1077-1082, 1998, and similar capabilities are available for the corn genome. Map information concerning chromosomal location is useful for proprietary protection of a subject transgenic plant. If unauthorized propagation is undertaken and crosses made with other germplasm, the map of the integration region can be compared to similar maps for suspect plants to determine if the latter have a common parentage with the subject plant. Map comparisons would involve hybridizations, RFLP, PCR, SSR and sequencing, all of which are conventional techniques. SNPs may also be used alone or in combination with other techniques.

Likewise, by means of the present invention, plants can be genetically engineered to express various phenotypes of agronomic interest. Through the transformation of maize the expression of genes can be altered to enhance disease resistance, insect resistance, herbicide resistance, agronomic traits, grain quality and other traits. Transformation can also be used to insert DNA sequences which control or help control male-sterility. DNA sequences native to maize as well as non-native DNA sequences can be transformed into maize and used to alter levels of native or non-native proteins. Various promoters, targeting sequences, enhancing sequences, and other DNA sequences can be inserted into the maize genome for the purpose of altering the expression of proteins. Reduction of the activity of specific genes (also known as gene silencing, or gene suppression) is desirable for several aspects of genetic engineering in plants.

Many techniques for gene silencing are well known to one of skill in the art, including but not limited to knock-outs (such as by insertion of a transposable element such as mu (Vicki Chandler, The Maize Handbook ch. 118 (Springer-Verlag 1994) or other genetic elements such as a FRT, Lox or other site specific integration site, antisense technology (see, e.g., Sheehy et al. (1988) PNAS USA 85:8805-8809; and U.S. Pat. Nos. 5,107,065; 5,453,566; and 5,759,829); co-suppression (e.g., Taylor (1997) Plant Cell 9:1245; Jorgensen (1990) Trends Biotech. 8(12):340-344; Flavell (1994) PNAS USA 91:3490-3496; Finnegan et al. (1994) Bio/Technology 12: 883-888; and Neuhuber et al. (1994) Mol. Gen. Genet. 244:230-241); RNA interference (Napoli et al. (1990) Plant Cell 2:279-289; U.S. Pat. No. 5,034,323; Sharp (1999) Genes Dev. 13:139-141; Zamore et al. (2000) Cell 101:25-33; and Montgomery et al. (1998) PNAS USA 95: 15502-15507), virus-induced gene silencing (Burton, et al. (2000) Plant Cell 12:691-705; and Baulcombe (1999) Curr. Op. Plant Bio. 2:109-113); target-RNA-specific ribozymes (Haseloff et al. (1988) Nature 334: 585-591); hairpin structures (Smith et al. (2000) Nature 407:319-320; WO 99/53050; and WO 98/53083); MicroRNA (Aukerman & Sakai (2003) Plant Cell 15:2730-2741); ribozymes (Steinecke et al. (1992) EMBO J. 11:1525; and Perriman et al. (1993) Antisense Res. Dev. 3:253); oligonucleotide mediated targeted modification (e.g., WO 03/076574 and WO 99/25853); Zn-finger targeted molecules (e.g., WO 01/52620; WO 03/048345; and WO 00/42219); and other methods or combinations of the above methods known to those of skill in the art.

Exemplary nucleotide sequences that may be altered by genetic engineering include, but are not limited to, those categorized below.

-   1. Transgenes that Confer Resistance to Insects or Disease and that     Encode:

(A) Plant disease resistance genes. Plant defenses are often activated by specific interaction between the product of a disease resistance gene (R) in the plant and the product of a corresponding avirulence (Avr) gene in the pathogen. A plant variety can be transformed with cloned resistance gene to engineer plants that are resistant to specific pathogen strains. See, for example Jones et al., Science 266: 789 (1994) (cloning of the tomato Cf-9 gene for resistance to Cladosporium fulvum); Martin et al., Science 262: 1432 (1993) (tomato Pto gene for resistance to Pseudomonas syringae pv. tomato encodes a protein kinase); Mindrinos et al., Cell 78: 1089 (1994) (Arabidopsis RSP2 gene for resistance to Pseudomonas syringae); McDowell & Woffenden, (2003) Trends Biotechnol. 21(4): 178-83 and Toyoda et al., (2002) Transgenic Res. 11(6):567-82. A plant resistant to a disease is one that is more resistant to a pathogen as compared to the wild type plant.

(B) A Bacillus thuringiensis protein, a derivative thereof or a synthetic polypeptide modeled thereon. See, for example, Geiser et al., Gene 48: 109 (1986), who disclose the cloning and nucleotide sequence of a Bt delta-endotoxin gene. Moreover, DNA molecules encoding delta-endotoxin genes can be purchased from American Type Culture Collection (Rockville, Md.), for example, under ATCC Accession Nos. 40098, 67136, 31995 and 31998. Other examples of Bacillus thuringiensis transgenes being genetically engineered are given in the following patents and patent applications and hereby are incorporated by reference for this purpose: U.S. Pat. Nos. 5,188,960; 5,689,052; 5,880,275; WO 91/14778; WO 99/31248; WO 01/12731; WO 99/24581; WO 97/40162 and U.S. application Ser. Nos. 10/032,717; 10/414,637; and 10/606,320.

(C) An insect-specific hormone or pheromone such as an ecdysteroid and juvenile hormone, a variant thereof, a mimetic based thereon, or an antagonist or agonist thereof. See, for example, the disclosure by Hammock et al., Nature 344: 458 (1990), of baculovirus expression of cloned juvenile hormone esterase, an inactivator of juvenile hormone.

(D) An insect-specific peptide which, upon expression, disrupts the physiology of the affected pest. For example, see the disclosures of Regan, J. Biol. Chem. 269: 9 (1994) (expression cloning yields DNA coding for insect diuretic hormone receptor); Pratt et al., Biochem. Biophys. Res. Comm. 163: 1243 (1989) (an allostatin is identified in Diploptera puntata); Chattopadhyay et al. (2004) Critical Reviews in Microbiology 30 (1): 33-54 2004; Zjawiony (2004) J Nat Prod 67 (2): 300-310; Carlini & Grossi-de-Sa (2002) Toxicon, 40 (11): 1515-1539; Ussuf et al. (2001) Curr Sci. 80 (7): 847-853; and Vasconcelos & Oliveira (2004) Toxicon 44 (4): 385-403. See also U.S. Pat. No. 5,266,317 to Tomalski et al., who disclose genes encoding insect-specific toxins.

(E) An enzyme responsible for a hyperaccumulation of a monterpene, a sesquiterpene, a steroid, hydroxamic acid, a phenylpropanoid derivative or another non-protein molecule with insecticidal activity.

(F) An enzyme involved in the modification, including the post-translational modification, of a biologically active molecule; for example, a glycolytic enzyme, a proteolytic enzyme, a lipolytic enzyme, a nuclease, a cyclase, a transaminase, an esterase, a hydrolase, a phosphatase, a kinase, a phosphorylase, a polymerase, an elastase, a chitinase and a glucanase, whether natural or synthetic. See PCT application WO 93/02197 in the name of Scott et al., which discloses the nucleotide sequence of a callase gene. DNA molecules which contain chitinase-encoding sequences can be obtained, for example, from the ATCC under Accession Nos. 39637 and 67152. See also Kramer et al., Insect Biochem. Molec. Biol. 23: 691 (1993), who teach the nucleotide sequence of a cDNA encoding tobacco hookworm chitinase, and Kawalleck et al., Plant Molec. Biol. 21: 673 (1993), who provide the nucleotide sequence of the parsley ubi4-2 polyubiquitin gene, U.S. application Ser. Nos. 10/389,432, 10/692,367, and U.S. Pat. No. 6,563,020.

(G) A molecule that stimulates signal transduction. For example, see the disclosure by Botella et al., Plant Molec. Biol. 24: 757 (1994), of nucleotide sequences for mung bean calmodulin cDNA clones, and Griess et al., Plant Physiol. 104: 1467 (1994), who provide the nucleotide sequence of a maize calmodulin cDNA clone.

(H) A hydrophobic moment peptide. See PCT application WO 95/16776 and U.S. Pat. No. 5,580,852 (disclosure of peptide derivatives of Tachyplesin which inhibit fungal plant pathogens) and PCT application WO 95/18855 and U.S. Pat. No. 5,607,914) (teaches synthetic antimicrobial peptides that confer disease resistance).

(I) A membrane permease, a channel former or a channel blocker. For example, see the disclosure by Jaynes et al., Plant Sci. 89: 43 (1993), of heterologous expression of a cecropin-beta lytic peptide analog to render transgenic tobacco plants resistant to Pseudomonas solanacearum.

(J) A viral-invasive protein or a complex toxin derived therefrom. For example, the accumulation of viral coat proteins in transformed plant cells imparts resistance to viral infection and/or disease development effected by the virus from which the coat protein gene is derived, as well as by related viruses. See Beachy et al., Ann. Rev. Phytopathol. 28: 451 (1990). Coat protein-mediated resistance has been conferred upon transformed plants against alfalfa mosaic virus, cucumber mosaic virus, tobacco streak virus, potato virus X, potato virus Y, tobacco etch virus, tobacco rattle virus and tobacco mosaic virus. Id.

(K) An insect-specific antibody or an immunotoxin derived therefrom. Thus, an antibody targeted to a critical metabolic function in the insect gut would inactivate an affected enzyme, killing the insect. Cf. Taylor et al., Abstract #497, SEVENTH INT'L SYMPOSIUM ON MOLECULAR PLANT-MICROBE INTERACTIONS (Edinburgh, Scotland, 1994) (enzymatic inactivation in transgenic tobacco via production of single-chain antibody fragments).

(L) A virus-specific antibody. See, for example, Tavladoraki et al., Nature 366: 469 (1993), who show that transgenic plants expressing recombinant antibody genes are protected from virus attack.

(M) A developmental-arrestive protein produced in nature by a pathogen or a parasite. Thus, fungal endo alpha-1,4-D-polygalacturonases facilitate fungal colonization and plant nutrient release by solubilizing plant cell wall homo-alpha-1,4-D-galacturonase. See Lamb et al., Bio/Technology 10: 1436 (1992). The cloning and characterization of a gene which encodes a bean endopolygalacturonase-inhibiting protein is described by Toubart et al., Plant J. 2: 367 (1992).

(N) A developmental-arrestive protein produced in nature by a plant. For example, Logemann et al., Bio/Technology 10: 305 (1992), have shown that transgenic plants expressing the barley ribosome-inactivating gene have an increased resistance to fungal disease.

(O) Genes involved in the Systemic Acquired Resistance (SAR) Response and/or the pathogenesis related genes. Briggs, S., Current Biology, 5(2):128-131 (1995), Pieterse & Van Loon (2004) Curr. Opin. Plant Bio. 7(4):456-64 and Somssich (2003) Cell 113(7):815-6.

(P) Antifungal genes (Cornelissen and Melchers, Pl. Physiol. 101:709-712, (1993) and Parijs et al., Planta 183:258-264, (1991) and Bushnell et al., Can. J. of Plant Path. 20(2):137-149 (1998). Also see U.S. application Ser. No. 09/950,933.

(Q) Detoxification genes, such as for fumonisin, beauvericin, moniliformin and zearalenone and their structurally related derivatives. For example, see U.S. Pat. No. 5,792,931.

(R) Cystatin and cysteine proteinase inhibitors. See U.S. application Ser. No. 10/947,979.

(S) Defensin genes. See WO03000863 and U.S. application Ser. No. 10/178,213.

(T) Genes conferring resistance to nematodes. See WO 03/033651 and Urwin et. al., Planta 204:472-479 (1998), Williamson (1999) Curr Opin Plant Bio. 2(4):327-31.

(U) Genes such as rcg1 conferring resistance to Anthracnose stalk rot, which is caused by the fungus Colletotrichum graminiola. See M. Jung et al., Generation-means analysis and quantitative trait locus mapping of Anthracnose Stalk Rot genes in Maize, Theor. Appl. Genet. (1994) 89:413-418 which is incorporated by reference for this purpose, as well as U.S. Patent Application 60/675,664, which is also incorporated by reference for this purpose.

-   2. Transgenes that Confer Resistance to a Herbicide, for Example:

(A) A herbicide that inhibits the growing point or meristem, such as an imidazolinone or a sulfonylurea. Exemplary genes in this category code for mutant ALS and AHAS enzyme as described, for example, by Lee et al., EMBO J. 7: 1241 (1988), and Miki et al., Theor. Appl. Genet. 80: 449 (1990), respectively. See also, U.S. Pat. Nos. 5,605,011; 5,013,659; 5,141,870; 5,767,361; 5,731,180; 5,304,732; 4,761,373; 5,331,107; 5,928,937; and 5,378,824; and international publication WO 96/33270, which are incorporated herein by reference for this purpose.

(B) Glyphosate (resistance imparted by mutant 5-enolpyruvl-3-phosphikimate synthase (EPSP) and aroA genes, respectively) and other phosphono compounds such as glufosinate (phosphinothricin acetyl transferase (PAT) and Streptomyces hygroscopicus phosphinothricin acetyl transferase (bar) genes), and pyridinoxy or phenoxy proprionic acids and cycloshexones (ACCase inhibitor-encoding genes). See, for example, U.S. Pat. No. 4,940,835 to Shah et al., which discloses the nucleotide sequence of a form of EPSPS which can confer glyphosate resistance. U.S. Pat. No. 5,627,061 to Barry et al. also describes genes encoding EPSPS enzymes. See also U.S. Pat. Nos. 6,566,587; 6,338,961; 6,248,876 B1; 6,040,497; 5,804,425; 5,633,435; 5,145,783; 4,971,908; 5,312,910; 5,188,642; 4,940,835; 5,866,775; 6,225,114 B1; 6,130,366; 5,310,667; 4,535,060; 4,769,061; 5,633,448; 5,510,471; Re. 36,449; RE 37,287 E; and 5,491,288; and international publications EP1173580; WO 01/66704; EP1173581 and EP1173582, which are incorporated herein by reference for this purpose. Glyphosate resistance is also imparted to plants that express a gene that encodes a glyphosate oxido-reductase enzyme as described more fully in U.S. Pat. Nos. 5,776,760 and 5,463,175, which are incorporated herein by reference for this purpose. In addition glyphosate resistance can be imparted to plants by the over expression of genes encoding glyphosate N-acetyltransferase. See, for example, U.S. application Ser. Nos. US01/46227; 10/427,692 and 10/427,692. A DNA molecule encoding a mutant aroA gene can be obtained under ATCC accession No. 39256, and the nucleotide sequence of the mutant gene is disclosed in U.S. Pat. No. 4,769,061 to Comai. European Patent Application No. 0 333 033 to Kumada et al. and U.S. Pat. No. 4,975,374 to Goodman et al. disclose nucleotide sequences of glutamine synthetase genes which confer resistance to herbicides such as L-phosphinothricin. The nucleotide sequence of a phosphinothricin-acetyl-transferase gene is provided in European Patent No. 0 242 246 and 0 242 236 to Leemans et al. De Greef et al., Bio/Technology 7: 61 (1989), describe the production of transgenic plants that express chimeric bar genes coding for phosphinothricin acetyl transferase activity. See also, U.S. Pat. Nos. 5,969,213; 5,489,520; 5,550,318; 5,874,265; 5,919,675; 5,561,236; 5,648,477; 5,646,024; 6,177,616 B1; and 5,879,903, which are incorporated herein by reference for this purpose. Exemplary genes conferring resistance to phenoxy proprionic acids and cycloshexones, such as sethoxydim and haloxyfop, are the Acc1-S1, Acc1-S2 and Acc1-S3 genes described by Marshall et al., Theor. Appl. Genet. 83: 435 (1992).

(C) A herbicide that inhibits photosynthesis, such as a triazine (psbA and gs+ genes) and a benzonitrile (nitrilase gene). Przibilla et al., Plant Cell 3: 169 (1991), describe the transformation of Chlamydomonas with plasmids encoding mutant psbA genes. Nucleotide sequences for nitrilase genes are disclosed in U.S. Pat. No. 4,810,648 to Stalker, and DNA molecules containing these genes are available under ATCC Accession Nos. 53435, 67441 and 67442. Cloning and expression of DNA coding for a glutathione S-transferase is described by Hayes et al., Biochem. J. 285: 173 (1992).

(D) Acetohydroxy acid synthase, which has been found to make plants that express this enzyme resistant to multiple types of herbicides, has been introduced into a variety of plants (see, e.g., Hattori et al. (1995) Mol Gen Genet 246:419). Other genes that confer resistance to herbicides include: a gene encoding a chimeric protein of rat cytochrome P4507A1 and yeast NADPH-cytochrome P450 oxidoreductase (Shiota et al. (1994) Plant Physiol. 106(1):17-23), genes for glutathione reductase and superoxide dismutase (Aono et al. (1995) Plant Cell Physiol 36:1687, and genes for various phosphotransferases (Datta et al. (1992) Plant Mol Biol 20:619).

(E) Protoporphyrinogen oxidase (protox) is necessary for the production of chlorophyll, which is necessary for all plant survival. The protox enzyme serves as the target for a variety of herbicidal compounds. These herbicides also inhibit growth of all the different species of plants present, causing their total destruction. The development of plants containing altered protox activity which are resistant to these herbicides are described in U.S. Pat. Nos. 6,288,306 B1; 6,282,837 B1; and 5,767,373; and international publication WO 01/12825.

-   3. Transgenes that Confer or Contribute to an Altered Grain     Characteristic, Such As:

(A) Altered fatty acids, for example, by

-   -   (1) Down-regulation of stearoyl-ACP desaturase to increase         stearic acid content of the plant. See Knultzon et al., Proc.         Natl. Acad. Sci. USA 89: 2624 (1992) and WO99/64579 (Genes for         Desaturases to Alter Lipid Profiles in Corn),     -   (2) Elevating oleic acid via FAD-2 gene modification and/or         decreasing linolenic acid via FAD-3 gene modification (see U.S.         Pat. Nos. 6,063,947; 6,323,392; 6,372,965 and WO 93/11245),     -   (3) Altering conjugated linolenic or linoleic acid content, such         as in WO 01/12800,     -   (4) Altering LEC1, AGP, Dek1, Superal1, mi1ps, various Ipa genes         such as Ipa1, Ipa3, hpt or hggt. For example, see WO 02/42424,         WO 98/22604, WO 03/011015, U.S. Pat. No. 6,423,886, U.S. Pat.         No. 6,197,561, U.S. Pat. No. 6,825,397, US2003/0079247,         US2003/0204870, WO02/057439, WO03/011015 and Rivera-Madrid, R.         et. al. Proc. Natl. Acad. Sci. 92:5620-5624 (1995).

(B) Altered phosphorus content, for example, by the

-   -   (1) Introduction of a phytase-encoding gene would enhance         breakdown of phytate, adding more free phosphate to the         transformed plant. For example, see Van Hartingsveldt et al.,         Gene 127: 87 (1993), for a disclosure of the nucleotide sequence         of an Aspergillus niger phytase gene.     -   (2) Up-regulation of a gene that reduces phytate content. In         maize, this, for example, could be accomplished, by cloning and         then re-introducing DNA associated with one or more of the         alleles, such as the LPA alleles, identified in maize mutants         characterized by low levels of phytic acid, such as in Raboy et         al., Maydica 35: 383 (1990) and/or by altering inositol kinase         activity as in WO 02/059324, US2003/0009011, WO 03/027243,         US2003/0079247, WO 99/05298, U.S. Pat. No. 6,197,561, U.S. Pat.         No. 6,291,224, U.S. Pat. No. 6,391,348, WO2002/059324,         US2003/0079247, Wo98/45448, WO99/55882, WO01/04147.

(C) Altered carbohydrates effected, for example, by altering a gene for an enzyme that affects the branching pattern of starch or a gene altering thioredoxin such as NTR and/or TRX (see U.S. Pat. No. 6,531,648 which is incorporated by reference for this purpose) and/or a gamma zein knock out or mutant such as cs27 or TUSC27 or en27 (See U.S. Pat. No. 6,858,778 and US2005/0160488, US2005/0204418; which are incorporated by reference for this purpose). See Shiroza et al., J. Bacteriol. 170: 810 (1988) (nucleotide sequence of Streptococcus mutans fructosyltransferase gene), Steinmetz et al., Mol. Gen. Genet. 200: 220 (1985) (nucleotide sequence of Bacillus subtilis levansucrase gene), Pen et al., Bio/Technology 10: 292 (1992) (production of transgenic plants that express Bacillus licheniformis alpha-amylase), Elliot et al., Plant Molec. Biol. 21: 515 (1993) (nucleotide sequences of tomato invertase genes), Søgaard et al., J. Biol. Chem. 268: 22480 (1993) (site-directed mutagenesis of barley alpha-amylase gene), and Fisher et al., Plant Physiol. 102: 1045 (1993) (maize endosperm starch branching enzyme II), WO 99/10498 (improved digestibility and/or starch extraction through modification of UDP-D-xylose 4-epimerase, Fragile 1 and 2, Ref1, HCHL, C4H), U.S. Pat. No. 6,232,529 (method of producing high oil seed by modification of starch levels (AGP)). The fatty acid modification genes mentioned above may also be used to affect starch content and/or composition through the interrelationship of the starch and oil pathways.

(D) Altered antioxidant content or composition, such as alteration of tocopherol or tocotrienols. For example, see U.S. Pat. No. 6,787,683, US2004/0034886 and WO 00/68393 involving the manipulation of antioxidant levels through alteration of a phytl prenyl transferase (ppt), WO 03/082899 through alteration of a homogentisate geranyl geranyl transferase (hggt).

(E) Altered essential seed amino acids. For example, see U.S. Pat. No. 6,127,600 (method of increasing accumulation of essential amino acids in seeds), U.S. Pat. No. 6,080,913 (binary methods of increasing accumulation of essential amino acids in seeds), U.S. Pat. No. 5,990,389 (high lysine), WO99/40209 (alteration of amino acid compositions in seeds), WO99/29882 (methods for altering amino acid content of proteins), U.S. Pat. No. 5,850,016 (alteration of amino acid compositions in seeds), WO98/20133 (proteins with enhanced levels of essential amino acids), U.S. Pat. No. 5,885,802 (high methionine), U.S. Pat. No. 5,885,801 (high threonine), U.S. Pat. No. 6,664,445 (plant amino acid biosynthetic enzymes), U.S. Pat. No. 6,459,019 (increased lysine and threonine), U.S. Pat. No. 6,441,274 (plant tryptophan synthase beta subunit), U.S. Pat. No. 6,346,403 (methionine metabolic enzymes), U.S. Pat. No. 5,939,599 (high sulfur), U.S. Pat. No. 5,912,414 (increased methionine), WO98/56935 (plant amino acid biosynthetic enzymes), WO98/45458 (engineered seed protein having higher percentage of essential amino acids), WO98/42831 (increased lysine), U.S. Pat. No. 5,633,436 (increasing sulfur amino acid content), U.S. Pat. No. 5,559,223 (synthetic storage proteins with defined structure containing programmable levels of essential amino acids for improvement of the nutritional value of plants), WO96/01905 (increased threonine), WO95/15392 (increased lysine), US2003/0163838, US2003/0150014, US2004/0068767, U.S. Pat. No. 6,803,498, WO01/79516, and WO00/09706 (Ces A: cellulose synthase), U.S. Pat. No. 6,194,638 (hemicellulose), U.S. Pat. No. 6,399,859 and US2004/0025203 (UDPGdH), U.S. Pat. No. 6,194,638 (RGP).

4. Genes that Control Male-Sterility

There are several methods of conferring genetic male sterility available, such as multiple mutant genes at separate locations within the genome that confer male sterility, as disclosed in U.S. Pat. Nos. 4,654,465 and 4,727,219 to Brar et al. and chromosomal translocations as described by Patterson in U.S. Pat. Nos. 3,861,709 and 3,710,511. In addition to these methods, Albertsen et al., U.S. Pat. No. 5,432,068, describe a system of nuclear male sterility which includes: identifying a gene which is critical to male fertility; silencing this native gene which is critical to male fertility; removing the native promoter from the essential male fertility gene and replacing it with an inducible promoter; inserting this genetically engineered gene back into the plant; and thus creating a plant that is male sterile because the inducible promoter is not “on” resulting in the male fertility gene not being transcribed. Fertility is restored by inducing, or turning “on”, the promoter, which in turn allows the gene that confers male fertility to be transcribed.

(A) Introduction of a deacetylase gene under the control of a tapetum-specific promoter and with the application of the chemical N-Ac-PPT (WO 01/29237).

(B) Introduction of various stamen-specific promoters (WO 92/13956, WO 92/13957).

(C) Introduction of the barnase and the barstar gene (Paul et al. Plant Mol. Biol. 19:611-622, 1992).

For additional examples of nuclear male and female sterility systems and genes, see also, U.S. Pat. Nos. 5,859,341; 6,297,426; 5,478,369; 5,824,524; 5,850,014; and 6,265,640; all of which are hereby incorporated by reference.

5. Genes that create a site for site specific DNA integration. This includes the introduction of FRT sites that may be used in the FLP/FRT system and/or Lox sites that may be used in the Cre/Loxp system. For example, see Lyznik, et al., Site-Specific Recombination for Genetic Engineering in Plants, Plant Cell Rep (2003) 21:925-932 and WO 99/25821, which are hereby incorporated by reference. Other systems that may be used include the Gin recombinase of phage Mu (Maeser et al., 1991; Vicki Chandler, The Maize Handbook ch. 118 (Springer-Verlag 1994), the Pin recombinase of E. coli (Enomoto et al., 1983), and the R/RS system of the pSR1 plasmid (Araki et al., 1992). 6. Genes that affect abiotic stress resistance (including but not limited to flowering, ear and seed development, enhancement of nitrogen utilization efficiency, altered nitrogen responsiveness, drought resistance or tolerance, cold resistance or tolerance, and salt resistance or tolerance) and increased yield under stress. For example, see: WO 00/73475 where water use efficiency is altered through alteration of malate; U.S. Pat. No. 5,892,009, U.S. Pat. No. 5,965,705, U.S. Pat. No. 5,929,305, U.S. Pat. No. 5,891,859, U.S. Pat. No. 6,417,428, U.S. Pat. No. 6,664,446, U.S. Pat. No. 6,706,866, U.S. Pat. No. 6,717,034, WO2000060089, WO2001026459, WO2001035725, WO2001034726, WO2001035727, WO2001036444, WO2001036597, WO2001036598, WO2002015675, WO2002017430, WO2002077185, WO2002079403, WO2003013227, WO2003013228, WO2003014327, WO2004031349, WO2004076638, WO9809521, and WO9938977 describing genes, including CBF genes and transcription factors effective in mitigating the negative effects of freezing, high salinity, and drought on plants, as well as conferring other positive effects on plant phenotype; US2004/0148654 and WO01/36596 where abscisic acid is altered in plants resulting in improved plant phenotype such as increased yield and/or increased tolerance to abiotic stress; WO2000/006341, WO04/090143, U.S. application Ser. Nos. 10/817,483 and 09/545,334 where cytokinin expression is modified resulting in plants with increased stress tolerance, such as drought tolerance, and/or increased yield. Also see WO0202776, WO2003052063, JP2002281975, U.S. Pat. No. 6,084,153, WO0164898, U.S. Pat. Nos. 6,177,275, and 6,107,547 (enhancement of nitrogen utilization and altered nitrogen responsiveness). For ethylene alteration, see US20040128719, US20030166197 and WO200032761. For plant transcription factors or transcriptional regulators of abiotic stress, see e.g. US20040098764 or US20040078852.

Other genes and transcription factors that affect plant growth and agronomic traits such as yield, flowering, plant growth and/or plant structure, can be introduced or introgressed into plants, see e.g. WO97/49811 (LHY), WO98/56918 (ESD4), WO97/10339 and U.S. Pat. No. 6,573,430 (TFL), U.S. Pat. No. 6,713,663 (FT), WO96/14414 (CON), WO96/38560, WO01/21822 (VRN1), WO00/44918 (VRN2), WO99/49064 (GI), WO00/46358 (FRI), WO97/29123, U.S. Pat. No. 6,794,560, U.S. Pat. No. 6,307,126 (GAI), WO99/09174 (D8 and Rht), and WO2004076638 and WO2004031349 (transcription factors).

Using PHDWA to Develop Other Maize Inbreds

Inbred maize lines such as PHDWA are typically developed for use in the production of hybrid maize lines. However, inbred lines such as PHDWA also provide a source of breeding material that may be used to develop new maize inbred lines. Plant breeding techniques known in the art and used in a maize plant breeding program include, but are not limited to, recurrent selection, mass selection, bulk selection, mass selection, backcrossing, pedigree breeding, open pollination breeding, restriction fragment length polymorphism enhanced selection, genetic marker enhanced selection, making double haploids, and transformation. Often combinations of these techniques are used. The development of maize hybrids in a maize plant breeding program requires, in general, the development of homozygous inbred lines, the crossing of these lines, and the evaluation of the crosses. There are many analytical methods available to evaluate the result of a cross. The oldest and most traditional method of analysis is the observation of phenotypic traits but genotypic analysis may also be used.

Using PHDWA in a Breeding Program

This invention is directed to methods for producing a maize plant by crossing a first parent maize plant with a second parent maize plant wherein either the first or second parent maize plant is an inbred maize plant of the line PHDWA. The other parent may be any other maize plant, such as another inbred line or a plant that is part of a synthetic or natural population. Any such methods using the inbred maize line PHDWA are part of this invention: selfing, sibbing, backcrosses, mass selection, pedigree breeding, bulk selection, hybrid production, crosses to populations, and the like. These methods are well known in the art and some of the more commonly used breeding methods are described below. Descriptions of breeding methods can also be found in one of several reference books (e.g., Allard, Principles of Plant Breeding, 1960; Simmonds, Principles of Crop Improvement, 1979; Fehr, “Breeding Methods for Cultivar Development”, Production and Uses, 2^(nd) ed., Wilcox editor, 1987 the disclosure of which is incorporated herein by reference).

Pedigree Breeding

Pedigree breeding starts with the crossing of two genotypes, such as PHDWA and one other elite inbred line having one or more desirable characteristics that is lacking or which complements PHDWA. If the two original parents do not provide all the desired characteristics, other sources can be included in the breeding population. In the pedigree method, superior plants are selfed and selected in successive filial generations. In the succeeding filial generations the heterozygous condition gives way to homogeneous lines as a result of self-pollination and selection. Typically in the pedigree method of breeding, five or more successive filial generations of selfing and selection is practiced: F1→F2; F2→F3; F3→F4; F4→F5, etc. After a sufficient amount of inbreeding, successive filial generations will serve to increase seed of the developed inbred. Preferably, the inbred line comprises homozygous alleles at about 95% or more of its loci.

In addition to being used to create a backcross conversion, backcrossing can also be used in combination with pedigree breeding to modify PHDWA and a hybrid that is made using the modified PHDWA. As discussed previously, backcrossing can be used to transfer one or more specifically desirable traits from one line, the donor parent, to an inbred called the recurrent parent, which has overall good agronomic characteristics yet lacks that desirable trait or traits. However, the same procedure can be used to move the progeny toward the genotype of the recurrent parent but at the same time retain many components of the non-recurrent parent by stopping the backcrossing at an early stage and proceeding with selfing and selection. For example, an F1, such as a commercial hybrid, is created. This commercial hybrid may be backcrossed to one of its parent lines to create a BC1 or BC2. Progeny are selfed and selected so that the newly developed inbred has many of the attributes of the recurrent parent and yet several of the desired attributes of the non-recurrent parent. This approach leverages the value and strengths of the recurrent parent for use in new hybrids and breeding.

Therefore, an embodiment of this invention is a method of making a backcross conversion of maize inbred line PHDWA, comprising the steps of crossing a plant of maize inbred line PHDWA with a donor plant comprising a mutant gene or transgene conferring a desired trait, selecting an F1 progeny plant comprising the mutant gene or transgene conferring the desired trait, and backcrossing the selected F1 progeny plant to a plant of maize inbred line PHDWA. This method may further comprise the step of obtaining a molecular marker profile of maize inbred line PHDWA and using the molecular marker profile to select for a progeny plant with the desired trait and the molecular marker profile of PHDWA. In the same manner, this method may be used to produce an F1 hybrid seed by adding a final step of crossing the desired trait conversion of maize inbred line PHDWA with a different maize plant to make F1 hybrid maize seed comprising a mutant gene or transgene conferring the desired trait.

Recurrent Selection and Mass Selection

Recurrent selection is a method used in a plant breeding program to improve a population of plants. PHDWA is suitable for use in a recurrent selection program. The method entails individual plants cross pollinating with each other to form progeny. The progeny are grown and the superior progeny selected by any number of selection methods, which include individual plant, half-sib progeny, full-sib progeny, selfed progeny and topcrossing. The selected progeny are cross pollinated with each other to form progeny for another population. This population is planted and again superior plants are selected to cross pollinate with each other. Recurrent selection is a cyclical process and therefore can be repeated as many times as desired. The objective of recurrent selection is to improve the traits of a population. The improved population can then be used as a source of breeding material to obtain inbred lines to be used in hybrids or used as parents for a synthetic cultivar. A synthetic cultivar is the resultant progeny formed by the intercrossing of several selected inbreds.

Mass selection is a useful technique when used in conjunction with molecular marker enhanced selection. In mass selection seeds from individuals are selected based on phenotype and/or genotype. These selected seeds are then bulked and used to grow the next generation. Bulk selection requires growing a population of plants in a bulk plot, allowing the plants to self-pollinate, harvesting the seed in bulk and then using a sample of the seed harvested in bulk to plant the next generation. Instead of self pollination, directed pollination could be used as part of the breeding program.

Mutation Breeding

Mutation breeding is one of many methods that could be used to introduce new traits into PHDWA. Mutations that occur spontaneously or are artificially induced can be useful sources of variability for a plant breeder. The goal of artificial mutagenesis is to increase the rate of mutation for a desired characteristic. Mutation rates can be increased by many different means including temperature, long-term seed storage, tissue culture conditions, radiation; such as X-rays, Gamma rays (e.g. cobalt 60 or cesium 137), neutrons, (product of nuclear fission by uranium 235 in an atomic reactor), Beta radiation (emitted from radioisotopes such as phosphorus 32 or carbon 14), or ultraviolet radiation (preferably from 2500 to 2900 nm), or chemical mutagens (such as base analogues (5-bromo-uracil), related compounds (8-ethoxy caffeine), antibiotics (streptonigrin), alkylating agents (sulfur mustards, nitrogen mustards, epoxides, ethylenamines, sulfates, sulfonates, sulfones, lactones), azide, hydroxylamine, nitrous acid, or acridines. Once a desired trait is observed through mutagenesis the trait may then be incorporated into existing germplasm by traditional breeding techniques, such as backcrossing. Details of mutation breeding can be found in “Principles of Cultivar Development” Fehr, 1993 Macmillan Publishing Company, the disclosure of which is incorporated herein by reference. In addition, mutations created in other lines may be used to produce a backcross conversion of PHDWA that comprises such mutation.

Breeding with Molecular Markers

Molecular markers, which includes markers identified through the use of techniques such as Isozyme Electrophoresis, Restriction Fragment Length Polymorphisms (RFLPs), Randomly Amplified Polymorphic DNAs (RAPDS), Arbitrarily Primed Polymerase Chain Reaction (AP-PCR), DNA Amplification Fingerprinting (DAF), Sequence Characterized Amplified Regions (SCARs), Amplified Fragment Length Polymorphisms (AFLPs), Simple Sequence Repeats (SSRs) and Single Nucleotide Polymorphisms (SNPs), may be used in plant breeding methods utilizing PHDWA.

Isozyme Electrophoresis and RFLPs as discussed in Lee, M., “Inbred Lines of Maize and Their Molecular Markers,” The Maize Handbook, (Springer-Verlag, New York, Inc. 1994, at 423-432), have been widely used to determine genetic composition. Isozyme Electrophoresis has a relatively low number of available markers and a low number of allelic variants among maize inbreds. RFLPs allow more discrimination because they have a higher degree of allelic variation in maize and a larger number of markers can be found. Both of these methods have been eclipsed by SSRs as discussed in Smith et al., “An evaluation of the utility of SSR loci as molecular markers in maize (Zea mays L.): comparisons with data from RFLPs and pedigree”, Theoretical and Applied Genetics (1997) vol. 95 at 163-173 and by Pejic et al., “Comparative analysis of genetic similarity among maize inbreds detected by RFLPs, RAPDs, SSRs, and AFLPs,” Theoretical and Applied Genetics (1998) at 1248-1255 incorporated herein by reference. SSR technology is more efficient and practical to use than RFLPs; more marker loci can be routinely used and more alleles per marker locus can be found using SSRs in comparison to RFLPs. Single Nucleotide Polymorphisms may also be used to identify the unique genetic composition of the invention and progeny lines retaining that unique genetic composition. Various molecular marker techniques may be used in combination to enhance overall resolution.

Maize DNA molecular marker linkage maps have been rapidly constructed and widely implemented in genetic studies. One such study is described in Boppenmaier, et al., “Comparisons among strains of inbreds for RFLPs”, Maize Genetics Cooperative Newsletter, 65:1991, pg. 90, is incorporated herein by reference.

One use of molecular markers is Quantitative Trait Loci (QTL) mapping. QTL mapping is the use of markers, which are known to be closely linked to alleles that have measurable effects on a quantitative trait. Selection in the breeding process is based upon the accumulation of markers linked to the positive effecting alleles and/or the elimination of the markers linked to the negative effecting alleles from the plant's genome.

Molecular markers can also be used during the breeding process for the selection of qualitative traits. For example, markers closely linked to alleles or markers containing sequences within the actual alleles of interest can be used to select plants that contain the alleles of interest during a backcrossing breeding program. The markers can also be used to select for the genome of the recurrent parent and against the genome of the donor parent. Using this procedure can minimize the amount of genome from the donor parent that remains in the selected plants. It can also be used to reduce the number of crosses back to the recurrent parent needed in a backcrossing program. The use of molecular markers in the selection process is often called genetic marker enhanced selection.

Production of Double Haploids

The production of double haploids can also be used for the development of inbreds in the breeding program. For example, an F1 hybrid for which PHDWA is a parent can be used to produce double haploid plants. Double haploids are produced by the doubling of a set of chromosomes (1N) from a heterozygous plant to produce a completely homozygous individual. For example, see Wan et al., “Efficient Production of Doubled Haploid Plants Through Colchicine Treatment of Anther-Derived Maize Callus”, Theoretical and Applied Genetics, 77:889-892, 1989 and US2003/0005479. This can be advantageous because the process omits the generations of selfing needed to obtain a homozygous plant from a heterozygous source.

Haploid induction systems have been developed for various plants to produce haploid tissues, plants and seeds. The haploid induction system can produce haploid plants from any genotype by crossing a selected line (as female) with an inducer line. Such inducer lines for maize include Stock 6 (Coe, 1959, Am. Nat. 93:381-382; Sharkar and Coe, 1966, Genetics 54:453-464) RWS (see world wide web site www.uni-hohenheim.de/%7Eipspwww/350b/indexe.html#Project3), KEMS (Deimling, Roeber, and Geiger, 1997, Vortr. Pflanzenzuchtg 38:203-224), or KMS and ZMS (Chalyk, Bylich & Chebotar, 1994, MNL 68:47; Chalyk & Chebotar, 2000, Plant Breeding 119:363-364), and indeterminate gametophyte (ig) mutation (Kermicle 1969 Science 166:1422-1424). The disclosures of which are incorporated herein by reference.

Methods for obtaining haploid plants are also disclosed in Kobayashi, M. et al., Journ. of Heredity 71(1):9-14, 1980, Pollacsek, M., Agronomie (Paris) 12(3):247-251, 1992; Cho-Un-Haing et al., Journ. of Plant Biol., 1996, 39(3):185-188; Verdoodt, L., et al., Feb. 1998, 96(2):294-300; Genetic Manipulation in Plant Breeding, Proceedings International Symposium Organized by EUCARPIA, Sep. 8-13, 1985, Berlin, Germany; Chalyk et al., 1994, Maize Genet Coop. Newsletter 68:47; Chalyk, S. T., 1999, Maize Genet. Coop. Newsletter 73:53-54; Coe, R. H., 1959, Am. Nat. 93:381-382; Deimling, S. et al., 1997, Vortr. Pflanzenzuchtg 38:203-204; Kato, A., 1999, J. Hered. 90:276-280; Lashermes, P. et al., 1988, Theor. Appl. Genet. 76:570-572 and 76:405-410; Tyrnov, V. S. et al., 1984, Dokl. Akad. Nauk. SSSR 276:735-738; Zabirova, E. R. et al., 1996, Kukuruza I Sorgo N4, 17-19; Aman, M. A., 1978, Indian J. Genet Plant Breed 38:452-457; Chalyk S. T., 1994, Euphytica 79:13-18; Chase, S. S., 1952, Agron. J. 44:263-267; Coe, E. H., 1959, Am. Nat. 93:381-382; Coe, E. H., and Sarkar, K. R., 1964 J. Hered. 55:231-233; Greenblatt, I. M. and Bock, M., 1967, J. Hered. 58:9-13; Kato, A., 1990, Maize Genet. Coop. Newsletter 65:109-110; Kato, A., 1997, Sex. Plant Reprod. 10:96-100; Nanda, D. K. and Chase, S. S., 1966, Crop Sci. 6:213-215; Sarkar, K. R. and Coe, E. H., 1966, Genetics 54:453-464; Sarkar, K. R. and Coe, E. H., 1971, Crop Sci. 11:543-544; Sarkar, K. R. and Sachan J. K. S., 1972, Indian J. Agric. Sci. 42:781-786; Kermicle J. L., 1969, Mehta Yeshwant, M. R., Genetics and Molecular Biology, September 2000, 23(3):617-622; Tahir, M. S. et al. Pakistan Journal of Scientific and Industrial Research, August 2000, 43(4):258-261; Knox, R. E. et al. Plant Breeding, August 2000, 119(4):289-298; U.S. Pat. No. 5,639,951 and U.S. patent application Ser. No. 10/121,200, the disclosures of which are incorporated herein by reference.

Thus, an embodiment of this invention is a process for making a substantially homozygous PHDWA progeny plant by producing or obtaining a seed from the cross of PHDWA and another maize plant and applying double haploid methods to the F1 seed or F1 plant or to any successive filial generation. Such methods decrease the number of generations required to produce an inbred with similar genetics or characteristics to PHDWA. See Bernardo, R. and Kahler, A. L., Theor. Appl. Genet. 102:986-992, 2001.

In particular, a process of making seed retaining the molecular marker profile of maize inbred line PHDWA is contemplated, such process comprising obtaining or producing F1 hybrid seed for which maize inbred line PHDWA is a parent, inducing doubled haploids to create progeny without the occurrence of meiotic segregation, obtaining the molecular marker profile of maize inbred line PHDWA, and selecting progeny that retain the molecular marker profile of PHDWA.

Use of PHDWA in Tissue Culture

This invention is also directed to the use of PHDWA in tissue culture. As used herein, the term “tissue culture” includes plant protoplasts, plant cell tissue culture, cultured microspores, plant calli, plant clumps, and the like. As used herein, phrases such as “growing the seed” or “grown from the seed” include embryo rescue, isolation of cells from seed for use in tissue culture, as well as traditional growing methods.

Duncan, Williams, Zehr, and Widholm, Planta (1985) 165:322-332 reflects that 97% of the plants cultured that produced callus were capable of plant regeneration. Subsequent experiments with both inbreds and hybrids produced 91% regenerable callus that produced plants. In a further study in 1988, Songstad, Duncan & Widholm in Plant Cell Reports (1988), 7:262-265 reports several media additions that enhance regenerability of callus of two inbred lines. Other published reports also indicated that “nontraditional” tissues are capable of producing somatic embryogenesis and plant regeneration. K. P. Rao, et al., Maize Genetics Cooperation Newsletter, 60:64-65 (1986), refers to somatic embryogenesis from glume callus cultures and B. V. Conger, et al., Plant Cell Reports, 6:345-347 (1987) indicates somatic embryogenesis from the tissue cultures of maize leaf segments. Thus, it is clear from the literature that the state of the art is such that these methods of obtaining plants are, and were, “conventional” in the sense that they are routinely used and have a very high rate of success.

Tissue culture of maize, including tassel/anther culture, is described in U.S. 2002/0062506A1 and European Patent Application, publication EP0160,390, each of which are incorporated herein by reference for this purpose. Maize tissue culture procedures are also described in Green and Rhodes, “Plant Regeneration in Tissue Culture of Maize,” Maize for Biological Research (Plant Molecular Biology Association, Charlottesville, Va. 1982, at 367-372) and in Duncan, et al., “The Production of Callus Capable of Plant Regeneration from Immature Embryos of Numerous Zea Mays Genotypes,” 165 Planta 322-332 (1985). Thus, another aspect of this invention is to provide cells which upon growth and differentiation produce maize plants having the genotype and/or physiological and morphological characteristics of inbred line PHDWA.

Progeny Plants

All plants produced by the use of the methods described herein and that retain the unique genetic or trait combinations of PHDWA are within the scope of the invention. Progeny of the breeding methods described herein may be characterized in any number of ways, such as by traits retained in the progeny, pedigree and/or molecular markers. Combinations of these methods of characterization may be used.

Breeder's of ordinary skill in the art have developed the concept of an “essentially derived variety”, which is defined in 7 U.S.C. § 2104(a)(3) of the Plant Variety Protection Act and is hereby incorporated by reference. Varieties and plants that are essentially derived from PHDWA are within the scope of the invention.

Pedigree is a method used by breeders of ordinary skill in the art to describe the varieties. Varieties that are more closely related by pedigree are likely to share common genotypes and combinations of phenotypic characteristics. All breeders of ordinary skill in the art maintain pedigree records of their breeding programs. These pedigree records contain a detailed description of the breeding process, including a listing of all parental lines used in the breeding process and information on how such line was used. One embodiment of this invention is progeny plants and parts thereof with at least one ancestor that is PHDWA, and more specifically, where the pedigree of the progeny includes 1, 2, 3, 4, and/or 5 or less breeding crosses to a maize plant other than PHDWA or a plant that has PHDWA as a parent or other progenitor. A breeder of ordinary skill in the art would know if PHDWA were used in the development of a progeny line, and would also know how many crosses to a line other than PHDWA or line with PHDWA as a parent or other progenitor were made in the development of any progeny line.

Molecular markers also provide a means by which those of ordinary skill in the art characterize the similarity or differences of two lines. Using the breeding methods described herein, one can develop individual plants, plant cells, and populations of plants that retain at least 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5% genetic contribution from inbred line PHDWA, as measured by either percent identity or percent similarity. On average 50% of the starting germplasm would be expected to be passed to the progeny line after one cross to another line, 25% after another cross to a different line, and so on. With backcrossing, the expected contribution of PHDWA after 2, 3, 4 and 5 doses (or 1, 2, 3 and 4 backcrosses) would be 75%, 87.5%, 93.75% and 96.875% respectively. Actual genetic contribution may be much higher than the genetic contribution expected by pedigree, especially if molecular markers are used in selection. Molecular markers could also be used to confirm and/or determine the pedigree of the progeny line.

Traits are also used by those of ordinary skill in the art to characterize progeny. Traits are commonly evaluated at a significance level, such as a 1%, 5% or 10% significance level, when measured in plants grown in the same environmental conditions. For example, a backcross conversion of PHDWA may be characterized as having the same morphological and physiological traits as PHDWA. The traits used for comparison may be those traits shown in Table 1, Table 3, Table 4 or Table 5.

A breeder will commonly work to combine a specific trait of an undeveloped variety of the species, such as a high level of resistance to a particular disease, with one or more of the elite agronomic characteristics (yield, maturity, plant size, lodging resistance, etc.) needed for use as a commercial variety. This combination, once developed, provides a valuable source of new germplasm for further breeding. For example, it may take 10-15 years and significant effort to produce such a combination, yet progeny may be developed that retain this combination in as little as 2-5 years and with much less effort.

SPECIFIC EMBODIMENTS

Specific methods and products produced using inbred line PHDWA in plant breeding are discussed in the following sections. The methods outlined are described in detail by way of illustration and example for purposes of clarity and understanding. However, it will be obvious that certain changes and modifications may be practiced within the scope of the invention.

One method for producing a line derived from inbred line PHDWA is as follows. One of ordinary skill in the art would produce or obtain a seed from the cross between inbred line PHDWA and another variety of maize, such as an elite inbred variety. The F1 seed derived from this cross would be grown to form a homogeneous population. The F1 seed would contain essentially all of the alleles from variety PHDWA and essentially all of the alleles from the other maize variety. The F1 nuclear genome would be made-up of 50% variety PHDWA and 50% of the other elite variety. The F1 seed would be grown and allowed to self, thereby forming F2 seed. On average the F2 seed would have derived 50% of its alleles from variety PHDWA and 50% from the other maize variety, but many individual plants from the population would have a greater percentage of their alleles derived from PHDWA (Wang J. and R. Bernardo, 2000, Crop Sci. 40:659-665 and Bernardo, R. and A. L. Kahler, 2001, Theor. Appl. Genet. 102:986-992). The molecular markers of PHDWA could be used to select and retain those lines with high similarity to PHDWA. The F2 seed would be grown and selection of plants would be made based on visual observation, markers and/or measurement of traits. The traits used for selection may be any PHDWA trait described in this specification, including the inbred per se maize PHDWA traits described herein under the detailed description of inbred PHDWA. Such traits may also be the good general or specific combining ability of PHDWA, including its ability to produce hybrids with the approximate maturity and/or hybrid combination traits described herein under the detailed description of inbred PHDWA. The PHDWA progeny plants that exhibit one or more of the desired PHDWA traits, such as those listed herein, would be selected and each plant would be harvested separately. This F3 seed from each plant would be grown in individual rows and allowed to self. Then selected rows or plants from the rows would be harvested individually. The selections would again be based on visual observation, markers and/or measurements for desirable traits of the plants, such as one or more of the desirable PHDWA traits listed herein. The process of growing and selection would be repeated any number of times until a PHDWA progeny inbred plant is obtained. The PHDWA progeny inbred plant would contain desirable traits derived from inbred plant PHDWA, some of which may not have been expressed by the other maize variety to which inbred line PHDWA was crossed and some of which may have been expressed by both maize varieties but now would be at a level equal to or greater than the level expressed in inbred variety PHDWA. However, in each case the resulting progeny line would benefit from the efforts of the inventor(s), and would not have existed but for the inventor(s) work in creating PHDWA. The PHDWA progeny inbred plants would have, on average, 50% of their nuclear genes derived from inbred line PHDWA, but many individual plants from the population would have a greater percentage of their alleles derived from PHDWA. This breeding cycle, of crossing and selfing, and optional selection, may be repeated to produce another population of PHDWA progeny maize plants with, on average, 25% of their nuclear genes derived from inbred line PHDWA, but, again, many individual plants from the population would have a greater percentage of their alleles derived from PHDWA. This process can be repeated for a third, fourth, fifth, sixth, seventh or more breeding cycles. Another embodiment of the invention is a PHDWA progeny plant that has received the desirable PHDWA traits listed herein through the use of PHDWA, which traits were not exhibited by other plants used in the breeding process.

Therefore, an embodiment of this invention is a PHDWA progeny maize plant, wherein at least one ancestor of said PHDWA progeny maize plant is the maize plant or plant part of PHDWA, and wherein the pedigree of said PHDWA progeny maize plant is within two breeding crosses of PHDWA or a plant that has PHDWA as a parent. The progeny plants, parts and plant cells produced from PHDWA may be further characterized as having a percent marker similarity or identity with PHDWA as described herein.

The previous example can be modified in numerous ways, for instance selection may or may not occur at every selfing generation, selection may occur before or after the actual self-pollination process occurs, or individual selections may be made by harvesting individual ears, plants, rows or plots at any point during the breeding process described. Double haploid breeding methods may be used at any step in the process. Instead of selfing out of the hybrid produced from the inbred, one could first cross the hybrid to either a parent line or a different inbred, and then self out of that cross.

The population of plants produced at each and any cycle of breeding is also an embodiment of the invention, and on average each such population would predictably consist of plants containing approximately 50% of its genes from inbred line PHDWA in the first breeding cycle, 25% of its genes from inbred line PHDWA in the second breeding cycle, 12.5% of its genes from inbred line PHDWA in the third breeding cycle, 6.25% in the fourth breeding cycle, 3.125% in the fifth breeding cycle, and so on. However, in each case the use of PHDWA provides a substantial benefit. The linkage groups of PHDWA would be retained in the progeny lines, and since current estimates of the maize genome size is about 50,000-80,000 genes (Xiaowu, Gai et al., Nucleic Acids Research, 2000, Vol. 28, No. 1, 94-96), in addition to non-coding DNA that impacts gene expression, it provides a significant advantage to use PHDWA as starting material to produce a line that retains desired genetics or traits of PHDWA.

Therefore, an embodiment of the invention is a process for making a population of PHDWA progeny inbred maize plants comprising obtaining or producing a first generation progeny maize seed comprising the plant of PHDWA as a parent, growing said first generation progeny maize seed to produce first generation maize plants and obtaining self or sib pollinated seed from said first generation maize plants, and growing the self or sib pollinated seed to obtain a population of PHDWA progeny inbred maize plants.

The population of PHDWA progeny inbred maize plants produced by this method are also embodiments of the invention, and such population as a whole will retain the expected genetic contribution of PHDWA. An inbred line selected from the population of PHDWA progeny inbred maize plants produced by this method is an embodiment, and such line may be further characterized by its molecular marker identity or similarity to PHDWA.

In this manner, the invention also encompasses a process for making a PHDWA inbred progeny maize plant comprising the steps of obtaining or producing a first generation progeny maize seed wherein a parent of said first generation progeny maize seed is a PHDWA plant, growing said first generation progeny maize seed to produce a first generation maize plant and obtaining self or sib pollinated seed from said first generation maize plant, and producing successive filial generations to obtain a PHDWA inbred progeny maize plant. Also an embodiment of this invention is the first breeding cycle inbred PHDWA maize plant produced by this method.

Crosses to Other Species

The utility of inbred maize line PHDWA also extends to crosses with other species. Commonly, suitable species will be of the family Graminaceae, and especially of the genera Zea, Tripsacum, Coix, Schlerachne, Polytoca, Chionachne, and Trilobachne, of the tribe Maydeae. Potentially suitable for crosses with PHDWA may be the various varieties of grain sorghum, Sorghum bicolor (L.) Moench.

INDUSTRIAL APPLICABILITY

Maize is used as human food, livestock feed, and as raw material in industry. The food uses of maize, in addition to human consumption of maize kernels, include both products of dry- and wet-milling industries. The principal products of maize dry milling are grits, meal and flour. The maize wet-milling industry can provide maize starch, maize syrups, and dextrose for food use. Maize oil is recovered from maize germ, which is a by-product of both dry- and wet-milling industries.

Maize, including both grain and non-grain portions of the plant, is also used extensively as livestock feed, primarily for beef cattle, dairy cattle, hogs, and poultry.

Industrial uses of maize include production of ethanol, maize starch in the wet-milling industry and maize flour in the dry-milling industry. The industrial applications of maize starch and flour are based on functional properties, such as viscosity, film formation, adhesive properties, and ability to suspend particles. The maize starch and flour have application in the paper and textile industries. Other industrial uses include applications in adhesives, building materials, foundry binders, laundry starches, explosives, oil-well muds, and other mining applications.

Plant parts other than the grain of maize are also used in industry: for example, stalks and husks are made into paper and wallboard and cobs are used for fuel and to make charcoal.

The seed of inbred maize line PHDWA, the plant produced from the inbred seed, the hybrid maize plant produced from the crossing of the inbred, hybrid seed, and various parts of the hybrid maize plant and transgenic versions of the foregoing, can be utilized for human food, livestock feed, and as a raw material in industry.

REFERENCES

-   Aukerman, M. J. et al. (2003) “Regulation of Flowering Time and     Floral Organ Identity by a MicroRNA and Its APETALA2-like Target     Genes” The Plant Cell 15:2730-2741 -   Berry et al., Berry, Don et al., “Assessing Probability of Ancestry     Using Simple Sequence Repeat Profiles: Applications to Maize Hybrids     and Inbreds”, Genetics 161:813-824 (2002) -   Berry et al., “Assessing Probability of Ancestry Using Simple     Sequence Repeat Profiles: Applications to Maize Inbred Lines and     Soybean Varieties” Genetics 165:331-342 (2003) -   Boppenmaier, et al., “Comparisons Among Strains of Inbreds for     RFLPs”, Maize Genetics Cooperative Newsletter, 65:1991, p. 90 -   Conger, B. V., et al. (1987) “Somatic Embryogenesis From Cultured     Leaf Segments of Zea Mays”, Plant Cell Reports, 6:345-347 -   Duncan, D. R., et al. (1985) “The Production of Callus Capable of     Plant Regeneration From Immature Embryos of Numerous Zea Mays     Genotypes”, Planta, 165:322-332 -   Edallo, et al. (1981) “Chromosomal Variation and Frequency of     Spontaneous Mutation Associated with in Vitro Culture and Plant     Regeneration in Maize”, Maydica, XXVI:39-56 -   Fehr, Walt, Principles of Cultivar Development, pp. 261-286 (1987) -   Green, et al. (1975) “Plant Regeneration From Tissue Cultures of     Maize”, Crop Science, Vol. 15, pp. 417-421 -   Green, C. E., et al. (1982) “Plant Regeneration in Tissue Cultures     of Maize” Maize for Biological Research, pp. 367-372 -   Hallauer, A. R. et al. (1988) “Corn Breeding” Corn and Corn     Improvement, No. 18, pp. 463-481 -   Lee, Michael (1994) “Inbred Lines of Maize and Their Molecular     Markers”, The Maize Handbook, Ch. 65:423-432 -   Meghji, M. R., et al. (1984) “Inbreeding Depression, Inbred & Hybrid     Grain Yields, and Other Traits of Maize Genotypes Representing Three     Eras”, Crop Science, Vol. 24, pp. 545-549 -   Openshaw, S. J., et al. (1994) “Marker-assisted selection in     backcross breeding”. pp. 41-43. In Proceedings of the Symposium     Analysis of Molecular Marker Data. 5-7 Aug. 1994. Corvallis, Oreg.,     American Society for Horticultural Science/Crop Science Society of     America -   Phillips, et al. (1988) “Cell/Tissue Culture and In Vitro     Manipulation”, Corn & Corn Improvement, 3rd Ed., ASA Publication,     No. 18, pp. 345-387 -   Poehlman et al (1995) Breeding Field Crop, 4th Ed., Iowa State     University Press, Ames, Iowa, pp. 132-155 and 321-344 -   Rao, K. V., et al., (1986) “Somatic Embryogenesis in Glume Callus     Cultures”, Maize Genetics Cooperative Newsletter, No. 60, pp. 64-65 -   Sass, John F. (1977) “Morphology”, Corn & Corn Improvement, ASA     Publication, Madison, Wis. pp. 89-109 -   Smith, J. S. C., et al., “The Identification of Female Selfs in     Hybrid Maize: A Comparison Using Electrophoresis and Morphology”,     Seed Science and Technology 14, 1-8 -   Songstad, D. D. et al. (1988) “Effect of     ACC(1-aminocyclopropane-1-carboyclic acid), Silver Nitrate &     Norbonadiene on Plant Regeneration From Maize Callus Cultures”,     Plant Cell Reports, 7:262-265 -   Tomes, et al. (1985) “The Effect of Parental Genotype on Initiation     of Embryogenic Callus From Elite Maize (Zea Mays L.) Germplasm”,     Theor. Appl. Genet., Vol. 70, p. 505-509 -   Troyer, et al. (1985) “Selection for Early Flowering in Corn: 10     Late Synthetics”, Crop Science, Vol. 25, pp. 695-697 -   Umbeck, et al. (1983) “Reversion of Male-Sterile T-Cytoplasm Maize     to Male Fertility in Tissue Culture”, Crop Science, Vol. 23, pp.     584-588 -   Wan et al., “Efficient Production of Doubled Haploid Plants Through     Colchicine Treatment of Anther-Derived Maize Callus”, Theoretical     and Applied Genetics, 77:889-892, 1989 -   Wright, Harold (1980) “Commercial Hybrid Seed Production”,     Hybridization of Crop Plants, Ch. 8:161-176 -   Wych, Robert D. (1988) “Production of Hybrid Seed”, Corn and Corn     Improvement, Ch. 9, pp. 565-607     Deposits

Applicant has made a deposit of at least 2500 seeds of Inbred Maize Line PHDWA with the American Type Culture Collection (ATCC), Manassas, Va. 20110 USA, ATCC Deposit No. PTA-7766. The seeds deposited with the ATCC on Aug. 9, 2006 were taken from the deposit maintained by Pioneer Hi-Bred International, Inc., 7250 NW 62^(nd) Avenue, Johnson, Iowa 50131-1000 since prior to the filing date of this application. Access to this deposit will be available during the pendency of the application to the Commissioner of Patents and Trademarks and persons determined by the Commissioner to be entitled thereto upon request. Upon allowance of any claims in the application, the Applicant will make the deposit available to the public pursuant to 37 C.F.R. § 1.808. This deposit of the Inbred Maize Line PHDWA will be maintained in the ATCC depository, which is a public depository, for a period of 30 years, or 5 years after the most recent request, or for the enforceable life of the patent, whichever is longer, and will be replaced if it becomes nonviable during that period. Additionally, Applicant has or will satisfy all of the requirements of 37 C.F.R. §§1.801-1.809, including providing an indication of the viability of the sample upon deposit. Applicant has no authority to waive any restrictions imposed by law on the transfer of biological material or its transportation in commerce. Applicant does not waive any infringement of rights granted under this patent or under the Plant Variety Protection Act (7 USC 2321 et seq.). U.S. Plant Variety Protection of Inbred Maize Line PHDWA has been applied for. Unauthorized seed multiplication is prohibited.

TABLE 1 VARIETY DESCRIPTION INFORMATION PHDWA AVG STDEV N 1. TYPE: (Describe intermediate types in comments 3 section) 1 = Sweet, 2 = Dent, 3 = Flint, 4 = Flour, 5 = Pop and 6 = Ornamental. Comments: Flint Like 2. MATURITY: DAYS HEAT UNITS Days H. Units Emergence to 50% of plants in silk 64 1,429 Emergence to 50% of plants in pollen shed 63 1,402 10% to 90% pollen shed 2 54 50% Silk to harvest at 25% moisture 3. PLANT: Plant Height (to tassel tip) (cm) 223.9 18.02 10 Ear Height (to base of top ear node) (cm) 69.8 13.01 10 Length of Top Ear Internode (cm) 17.6 2.17 10 Average Number of Tillers per Plant 0.0 0.00 2 Average Number of Ears per Stalk 1.0 0.00 2 Anthocyanin of Brace Roots: 1 = Absent, 2 = Faint, 4 3 = Moderate, 4 = Dark 4. LEAF: Width of Ear Node Leaf (cm) 9.1 0.88 10 Length of Ear Node Leaf (cm) 76.6 4.22 10 Number of Leaves above Top Ear 5.9 0.74 10 Leaf Angle: (at anthesis, 2nd leaf above ear to 29.5 2.12 10 stalk above leaf) (Degrees) *Leaf Color: V. Dark Green Munsell: 7.5GY34 Leaf Sheath Pubescence: 1 = none to 9 = like peach fuzz 3 5. TASSEL: Number of Primary Lateral Branches 5.1 1.29 10 Branch Angle from Central Spike 26.1 7.23 10 Tassel Length: (from peduncle node to tassel tip), (cm). 53.2 4.18 10 Pollen Shed: 0 = male sterile, 9 = heavy shed 5 *Anther Color: Light Green Munsell: 10Y86 *Glume Color: Med. Green Munsell: 5GY66 *Bar Glumes (glume bands): 1 = absent, 2 = present 1 Peduncle Length: (from top leaf node to lower florets or 20.9 2.64 10 branches), (cm). 6a. EAR (Unhusked ear) *Silk color: Light Green Munsell: 5GY94 (3 days after silk emergence) *Fresh husk color: Med. Green Munsell: 5GY66 *Dry husk color: Buff Munsell: 2.5Y8.54 (65 days after 50% silking) Ear position at dry husk stage: 1 = upright, 2 = horizontal, 3 3 = pendant Husk Tightness: (1 = very loose, 9 = very tight) 3 Husk Extension (at harvest): 1 = short(ears exposed), 2 2 = medium (<8 cm), 3 = long (8-10 cm), 4 = v. long (>10 cm) 6b. EAR (Husked ear data) Ear Length (cm): 15.1 0.99 10 Ear Diameter at mid-point (mm) 42.4 1.51 10 Ear Weight (gm): 121.1 10.83 10 Number of Kernel Rows: 15.8 1.75 10 Kernel Rows: 1 = indistinct, 2 = distinct 2 Row Alignment: 1 = straight, 2 = slightly curved, 3 = spiral 2 Shank Length (cm): 10.2 1.32 10 Ear Taper: 1 = slight cylind., 2 = average, 3 = extreme conic. 2 7. KERNEL (Dried): Kernel Length (mm): 9.9 0.57 10 Kernel Width (mm): 8.1 0.57 10 Kernel Thickness (mm): 4.6 0.52 10 Round Kernels (shape grade) (%) 22.5 7.00 2 Aleurone Color Pattern: 1 = homozygous, 2 = segregating 1 *Aleurone Color: Yellow Munsell: 10YR714 *Hard Endo. Color: Yellow Munsell: 10YR610 Endosperm Type: 3 1 = sweet (su1), 2 = extra sweet (sh2), 3 = normal starch, 4 = high amylose starch, 5 = waxy starch, 6 = high protein, 7 = high lysine, 8 = super sweet (se), 9 = high oil, 10 = other Weight per 100 Kernels (unsized sample) (gm): 24.0 1.41 2 8. COB: *Cob Diameter at mid-point (mm): 24.4 1.17 10 *Cob Color: Red Munsell: 10R310 10. DISEASE RESISTANCE: (Rate from 1 = most-susceptable to 9 = most-resistant. Leave blank if not tested, leave race or strain options blank if polygenic.) A. LEAF BLIGHTS, WILTS, AND LOCAL INFECTION DISEASES Anthracnose Leaf Blight (Colletotrichum graminicola) Common Rust (Puccinia sorghi) Common Smut (Ustilago maydis) Eyespot (Kabatiella zeae) Goss's Wilt (Clavibacter michiganense spp. 5 Gray Leaf Spot (Cercospora zeae-maydis) Helminthosporium Leaf Spot (Bipolaris zeicola) Race: 5 Northern Leaf Blight (Exserohilum turcicum) Race: Southern Leaf Blight (Bipolaris maydis) Race: Southern Rust (Puccinia polysora) Stewart's Wilt (Erwinia stewartii) Other (Specify):           B. SYSTEMIC DISEASES Corn Lethal Necrosis (MCMV and MDMV) 54 Head Smut (Sphacelotheca reiliana) (% infected) Maize Chlorotic Dwarf Virus (MDV) Maize Chlorotic Mottle Virus (MCMV) Maize Dwarf Mosaic Virus (MDMV) Sorghum Downy Mildew of Corn (Peronosclerospora sorghi) Other (Specify):           C. STALK ROTS 4 Anthracnose Stalk Rot (Colletotrichum graminicola) Diplodia Stalk Rot (Stenocarpella maydis) Fusarium Stalk Rot (Fusarium moniliforme) Gibberella Stalk Rot (Gibberella zeae) Other (Specify):           D. EAR AND KERNEL ROTS Aspergillus Ear and Kernel Rot (Aspergillus flavus) 3 Diplodia Ear Rot (Stenocarpella maydis) 5 Fusarium Ear and Kernel Rot (Fusarium moniliforme) Gibberella Ear Rot (Gibberella zeae) Other (Specify):           11. INSECT RESISTANCE: (Rate from 1 = most-suscept. to 9 = most-resist., leave blank if not tested.) Corn Worm (Helicoverpa zea)     Leaf Feeding     Silk Feeding     Ear Damage Corn Leaf Aphid (Rophalosiphum maydis) Corn Sap Beetle (Capophilus dimidiatus) European Corn Borer (Ostrinia nubilalis) 1st. Generation (Typically whorl leaf feeding) 2nd. Generation (Typically leaf sheath-collar feeding)     Stalk Tunneling     cm tunneled/plant Fall armyworm (Spodoptera fruqiperda)     Leaf Feeding     Silk Feeding     mg larval wt. Maize Weevil (Sitophilus zeamaize) Northern Rootworm (Diabrotica barberi) Southern Rootworm (Diabrotica undecimpunctata) Southwestern Corn Borer (Diatreaea grandiosella)     Leaf Feeding     Stalk Tunneling     cm tunneled/plant Two-spotted Spider Mite (Tetranychus utricae) Western Rootworm (Diabrotica virgifrea virgifrea) Other (Specify):           12. AGRONOMIC TRAITS: 2 Staygreen (at 65 days after anthesis; rate from 1-worst to 9-excellent) % Dropped Ears (at 65 days after anthesis) % Pre-anthesis Brittle Snapping 23 % Pre-anthesis Root Lodging % Post-anthesis Root Lodging (at 65 days after anthesis) % Post-anthesis Stalk Lodging 3,941.0 Kg/ha (Yield at 12-13% grain moisture) *Munsell Glossy Book of color, (A standard color reference). Kollmorgen Inst. Corp. New Windsor, NY.

TABLE 2 SSR PROFILE DATA FOR PHDWA. Bin Marker Name Base Pairs 1 UMC1354 379.5 1.01 TUB1 249.2 1.01 UMC2224 354.7 1.02 BNLG1127 96.4 1.02 BNLG1429 190.4 1.02 BNLG1953 199.9 1.02 UMC1711 251.3 1.02 UMC2383 206.4 1.03 PHI109275 132 1.03 UMC1701 117.7 1.04 BNLG2086 218.1 1.04 BNLG2238 204.5 1.04 UMC1144 230.3 1.04 UMC1472 218.9 1.04 UMC2228 218.8 1.04 UMC2390 146.3 1.05 UMC1244 341 1.05 UMC1626 143.8 1.05 UMC1689 146.5 1.05 UMC1703 144.4 1.05 UMC1906 158.8 1.05 UMC2025 131.2 1.05 UMC2232 133 1.06 BNLG1057 249 1.06 UMC1035 227.4 1.06 UMC1254 162.7 1.06 UMC1398 164.3 1.06 UMC1709 339.7 1.06 UMC1919 156.8 1.06 UMC1924 161.3 1.06 UMC2234 144.1 1.06 UMC2237 155.6 1.07 BNLG1556 207.5 1.07 UMC2387 112.3 1.08 UMC1838 170.2 1.08 UMC1991 224.1 1.08 UMC2029 156.8 1.08 UMC2181 100 1.08 UMC2240 239.8 1.08 UMC2385 265.5 1.09 BNLG1331 148.3 1.09 GLB1 218.6 1.09 UMC1715 137.7 1.09 UMC2028 116.4 1.09 UMC2047 141.8 1.1 PHI308707 131.2 1.1 UMC1885 140.4 1.1 UMC2189 112.1 1.11 PHI265454 217.5 1.11 UMC1681 138.1 1.11 UMC2241 333.4 1.11 UMC2242 345 1.12 UMC1797 109.1 2.01 UMC2363 339.1 2.02 BNLG1327 272.8 2.02 UMC1824A 138.1 2.03 BNLG1064 187.9 2.03 UMC1845 141.7 2.03 UMC2246 151.8 2.04 PRP2 123.6 2.04 UMC1326 139.8 2.04 UMC1861 307.9 2.04 UMC2007 116.8 2.04 UMC2030 81.8 2.04 UMC2032 158.6 2.04 UMC2247 253.8 2.04 UMC2248 141.6 2.05 UMC1459 107.2 2.05 UMC1635 140.1 2.05 UMC2252 108.4 2.05 UMC2254 99.8 2.06 BNLG1036 193.1 2.06 BNLG1138 224.1 2.06 BNLG1831 190.3 2.06 UMC1004 150.4 2.06 UMC1156 234.9 2.06 UMC1658 142.4 2.06 UMC1749 206.3 2.06 UMC1875 142.7 2.06 UMC1946 78.7 2.06 UMC2178 312.3 2.06 UMC2192 336 2.07 PHI251315 124 2.07 UMC2374 239 2.08 BNLG1141 152.9 2.08 BNLG1940 247.8 2.08 PHI435417 214 2.08 UMC1049 134.4 2.08 UMC1126 133.3 2.08 UMC1745 218.1 2.08 UMC1947 127 2.08 UMC2005 105.7 2.08 UMC2202 338 2.09 UMC1525 215.7 2.09 UMC1551 249.6 2.1 PHI101049 245 2.1 UMC2184 124.4 2.1 UMC2214 239.3 3 PHI453121 217.6 3 UMC1931 99.6 3.01 UMC1892 101.6 3.01 UMC2049 159.5 3.01 UMC2256 175 3.01 UMC2376 149.6 3.02 BNLG1647 164.1 3.02 PHI243966 211.5 3.02 UMC1814 337.3 3.02 UMC1886 148.3 3.02 UMC2258 141.2 3.04 BNLG1019A 155 3.04 TPI4 150.7 3.04 UMC1025 155.6 3.04 UMC1347 228.4 3.04 UMC1655 158.6 3.04 UMC1683 84.9 3.04 UMC1908 133.7 3.04 UMC2033 89.7 3.04 UMC2261 135.6 3.04 UMC2262 136.5 3.04 UMC2263 393.3 3.05 GST4 191.1 3.05 UMC1300 164.3 3.05 UMC1307 134.3 3.05 UMC1907 117.6 3.05 UMC1954 344.3 3.05 UMC2020 123.4 3.05 UMC2265 211.8 3.06 BNLG1160 222.3 3.06 BNLG1951 127.1 3.06 BNLG2241 116.5 3.06 PHI102228 135.7 3.06 UMC1311 210 3.06 UMC1644 164.4 3.06 UMC1674 128.5 3.06 UMC2270 139.9 3.07 UMC1286 228.1 3.07 UMC1659 122 3.07 UMC1825 164.1 3.07 UMC2050 129 3.08 UMC1844 127.9 3.08 UMC1915 92 3.08 UMC2276 135.3 3.09 BNLG1496 217.8 3.09 UMC1641 228.5 3.09 UMC1813 165.2 3.1 UMC2048 361.9 4 MTL1 139.9 4.01 UMC1757 185 4.04 ZP1 235.1 4.05 BNLG1217 202.4 4.05 BNLG1265 214 4.05 BNLG1755 216.8 4.05 GPC1 177.8 4.05 UMC1175 280.1 4.05 UMC1346 97 4.05 UMC1662 112.1 4.05 UMC1702 94.7 4.05 UMC1851 114.4 4.05 UMC1964 149.6 4.05 UMC2054 151.3 4.05 UMC2061 130.7 4.06 BNLG252 167.8 4.06 UMC1869 151.5 4.06 UMC1945 113.5 4.06 UMC2027 116.6 4.07 UMC1194 167.4 4.07 UMC1620 148.3 4.07 UMC1651 97.4 4.07 UMC1847 151.6 4.07 UMC2038 122.2 4.08 BNLG2162 153.4 4.08 PDH1 110.8 4.08 SSU1 279.7 4.08 UMC1371 163.3 4.08 UMC1418 147.9 4.08 UMC1559 141.1 4.08 UMC1612 108.7 4.08 UMC1667 154.6 4.08 UMC1834 169 4.08 UMC1899 111.8 4.08 UMC2187 87 4.08 UMC2188 167.9 4.09 RPD3 159.9 4.09 UMC1284 144.5 4.09 UMC1328 161.4 4.09 UMC1650 139.8 4.09 UMC1820 138.9 4.09 UMC1940 113.7 4.09 UMC1999 111.1 4.09 UMC2046 143.8 4.1 BNLG589 165.9 4.11 CAT3 170 5 UMC1240 213.4 5 UMC2022 152.4 5 UMC2292 137.5 5.01 UMC2036 158.5 5.03 PHI109188 167.4 5.03 UMC1315 156.3 5.03 UMC1355 356.8 5.03 UMC1475 260.4 5.03 UMC1686 96.7 5.03 UMC1692 166.5 5.03 UMC1731 361.9 5.03 UMC1784 337 5.03 UMC1830 182.5 5.03 UMC1850 125.3 5.03 UMC2035 110.8 5.03 UMC2294 98.7 5.03 UMC2295 121.3 5.03 UMC2297 141.8 5.04 BNLG2323 209.7 5.04 UMC1092 134.4 5.04 UMC1162 131 5.04 UMC1629 114.3 5.04 UMC1815 274.5 5.04 UMC1860 157.2 5.04 UMC1990 136.1 5.04 UMC2298 83 5.04 UMC2299 116.2 5.04 UMC2302 356.1 5.04 UMC2400 211.7 5.04 UMC2407 207.9 5.05 PHI333597 213.4 5.05 UMC1687 152.4 5.05 UMC1800 147.8 5.05 UMC1853 115 5.05 UMC2026 92.6 5.06 UMC1941 113.1 5.06 UMC2305 166.3 5.06 UMC2306 105.6 5.07 BNLG1118 80.6 5.07 UMC1537 325.1 5.07 UMC2013 125.3 5.07 UMC2198 140.5 5.07 UMC2201 165.7 5.09 UMC1829 163.8 5.09 UMC2209 167.8 6 FDX2 123.6 6 GPC2 346.4 6 UMC1753 200.7 6 UMC1883 84.2 6.01 CYC3 268.9 6.01 UMC1195 134.5 6.01 UMC1376 258.4 6.01 UMC1625 135.2 6.01 UMC2056 164.1 6.02 SAUR1 113.5 6.02 UMC1656 135.9 6.04 UMC1857 146.1 6.04 UMC1918 163.3 6.04 UMC2006 174.1 6.04 UMC2317 123.9 6.05 BNLG1174 218.9 6.05 PMG1 136.7 6.05 ROA2 351.4 6.05 UMC1314 342.2 6.05 UMC1352 148.8 6.05 UMC1413 303 6.05 UMC1795 128.2 6.05 UMC1805 100.2 6.06 UMC1462 211.3 6.06 UMC1859 106.6 6.06 UMC1912 169.2 6.07 BNLG1740 236.7 6.07 BNLG1759A 128.1 6.07 PHI299852 119.7 6.07 TLK1 81.1 6.07 UMC1350 120.1 6.07 UMC1653 198.2 6.07 UMC1897 157 7 BNLG2132 200.2 7 UMC1378 126.3 7 UMC1642 150.1 7.01 O2 431.3 7.01 UMC1159 228.2 7.01 UMC1632 150.2 7.02 BNLG1094 143 7.02 CYP6 138.1 7.02 KPP1 325.8 7.02 UMC1929 159.3 7.02 UMC1978 115.4 7.03 BNLG1070 145.6 7.03 BNLG155 225.5 7.03 BNLG2271 220.1 7.03 UMC1324 214.8 7.03 UMC1660 207.8 7.03 UMC1713 139.5 7.03 UMC1841 117.3 7.03 UMC1865 148.2 7.03 UMC1888 149 7.04 PHI328175 122.5 7.04 RIP2 321.3 7.04 UMC1342 220.1 7.04 UMC1708 332.6 7.04 UMC1710 235.3 7.05 PHI069 195.3 7.06 PHI116 169 8.01 UMC2042 110.8 8.02 UMC1304 251.5 8.02 UMC1790 155.8 8.02 UMC1913 162.4 8.02 UMC1974 486.3 8.02 UMC2004 126.4 8.03 BNLG1863 244.5 8.03 PHI100175 144 8.03 PHI121 97.9 8.03 UMC1289 221.7 8.03 UMC1377 216.2 8.03 UMC1487 338.5 8.03 UMC1904 155.4 8.04 BNLG2046 320.5 8.04 UMC1343 323.5 8.04 UMC1858 128 8.05 BNLG1176 218.2 8.05 UMC1141 306.9 8.05 UMC1287 306.4 8.05 UMC1316 233.3 8.05 UMC1846 105.8 8.05 UMC1864 170.8 8.05 UMC1889 113.7 8.06 BNLG1031 288.2 8.06 UMC1149 216.7 8.06 UMC1161 257.9 8.07 BNLG1065 215.8 8.07 BNLG1828 186 8.08 GST1 81.5 8.08 UMC1933 113.9 8.08 UMC2052 146.3 8.09 PHI233376 135.8 8.09 UMC1638 147.7 8.09 UMC1663 175.8 9.01 BNLG1810 205.1 9.01 SH1 249 9.01 UMC1040 219.5 9.01 UMC1809 230.6 9.01 UMC1867 230.7 9.02 UMC1131 362.4 9.02 UMC1170 230.1 9.02 UMC1636 195.4 9.02 UMC1698 116.8 9.02 UMC1893 98.5 9.02 UMC2213 106.6 9.02 UMC2336 258.4 9.03 BNLG127 244.4 9.03 UMC1420 313.5 9.03 UMC1634 113.9 9.03 UMC1688 305.6 9.03 UMC1691 149.5 9.03 UMC2337 130 9.04 BNLG1012 171.1 9.04 BNLG1159B 148 9.04 UMC1519 256.4 9.04 UMC2398 126.2 9.05 MMP179 161.3 9.05 UMC1357 257.1 9.05 UMC1654 111.4 9.05 UMC1794 118.5 9.05 UMC2338 105.1 9.05 UMC2341 130.3 9.05 UMC2343 132.4 9.06 PHI448880 182.7 9.06 UMC2207 115.6 9.06 UMC2346 297.3 9.06 UMC2358 135.2 9.07 BNLG1375 118 9.07 BNLG619 273 9.07 DUPSSR29 134.6 9.07 UMC1104 210.8 9.07 UMC1675 162.3 9.07 UMC1714 161.6 9.07 UMC1942 134.7 9.07 UMC2347 136.4 9.08 BNLG1129 298.5 10 PHI041 214.8 10.01 UMC2018 151.8 10.01 UMC2053 103.8 10.02 PHI059 153.1 10.02 UMC1337 311.8 10.02 UMC1432 119 10.02 UMC1582 275.6 10.02 UMC2034 133.2 10.02 UMC2069 375.9 10.03 BNLG1079 170.5 10.03 UMC1312 316 10.03 UMC1336 310 10.03 UMC1345 166.7 10.03 UMC1381 210.2 10.03 UMC1863 161.8 10.03 UMC1938 160.3 10.03 UMC1962 126.3 10.03 UMC2016 129.4 10.03 UMC2067 165.4 10.04 MGS1 161.3 10.04 UMC1330 340.3 10.04 UMC1589 114.3 10.04 UMC1648 141.6 10.04 UMC1697 97 10.04 UMC1930 125 10.04 UMC2003 89.3 10.05 BNLG1074 171.8 10.06 BNLG1028 137.9 10.06 UMC1993 127.4 10.07 BNLG1450 190 10.07 BNLG1839 187 10.07 UMC1556 245.6 10.07 UMC1640 107.9 10.07 UMC1645 158.9 10.07 UMC2021 135.2

TABLE 3A PAIRED INBRED COMPARISON REPORT Variety #1: PHDWA Variety #2: PH581 EGRWTH ESTCNT TILLER GDUSHD GDUSLK SCORE COUNT PCT GDU GDU TASSZ Stat ABS ABS ABS ABS ABS SCORE ABS Mean1 6.1 36.5 2.1 145.3 148.4 5.0 Mean2 6.1 36.6 1.2 134.9 138.3 4.8 Locs 16 23 25 81 79 71 Reps 16 23 25 81 79 71 Diff 0.0 −0.1 −0.9 10.4 10.1 0.2 Prob 1.000 0.897 0.228 0.000 0.000 0.217 STAGRN SCTGRN TEXEAR PLTHT CM EARHT CM SCORE SCORE SCORE BARPLT Stat ABS ABS ABS ABS ABS % NOT ABS Mean1 211.9 80.9 2.9 8.0 7.0 98.3 Mean2 190.8 68.8 2.4 8.0 7.0 97.8 Locs 60 29 13 6 2 38 Reps 60 29 13 6 2 38 Diff 21.1 12.1 0.5 0.0 0.0 0.5 Prob 0.000 0.000 0.279 1.000 1.000 0.422 GLFSPT STWWLT FUSERS COMRST ERTLPN SCORE SCORE SCORE SCORE % NOT Stat ABS ABS ABS ABS ABS Mean1 6.1 4.0 7.5 8.0 88.0 Mean2 5.9 4.0 7.5 6.0 94.0 Locs 8 2 2 1 5 Reps 8 2 2 1 5 Diff 0.3 0.0 0.0 2.0 −6.0 Prob 0.451 1.000 1.000 — 0.208

TABLE 3B PAIRED INBRED COMPARISON REPORT Variety #1: PHDWA Variety #2: PH1BC EGRWTH ESTCNT TILLER GDUSHD GDUSLK SCORE COUNT PCT GDU GDU Stat ABS ABS ABS ABS ABS Mean1 5.9 31.8 1.3 145.5 148.3 Mean2 5.9 31.4 1.5 149.4 150.5 Locs 11 10 22 63 61 Reps 11 11 22 63 61 Diff 0.0 0.4 0.2 −3.9 −2.2 Prob 1.000 0.716 0.804 0.000 0.000 POLWT POLWT TASSZ PLTHT EARHT VALUE VALUE SCORE CM CM Stat ABS % MN ABS ABS ABS Mean1 102.3 69.1 4.8 208.3 78.8 Mean2 137.3 91.6 5.2 238.4 89.1 Locs 14 14 57 56 27 Reps 27 27 57 57 28 Diff −35.1 −22.5 −0.4 −30.1 −10.3 Prob 0.019 0.039 0.015 0.000 0.000 STAGRN SCTGRN TEXEAR BARPLT GLFSPT SCORE SCORE SCORE % NOT SCORE Stat ABS ABS ABS ABS ABS Mean1 2.0 7.0 7.0 97.0 5.4 Mean2 2.4 8.3 9.0 96.4 5.4 Locs 14 3 1 27 18 Reps 16 3 1 27 28 Diff −0.4 −1.3 −2.0 0.6 0.1 Prob 0.355 0.423 — 0.713 0.854 NLFBLT SLFBLT STWWLT ANTROT FUSERS SCORE SCORE SCORE SCORE SCORE Stat ABS ABS ABS ABS ABS Mean1 5.3 3.3 3.5 3.8 4.3 Mean2 6.6 4.5 6.0 3.5 5.0 Locs 4 2 2 6 6 Reps 8 4 2 11 12 Diff −1.4 −1.3 −2.5 0.3 −0.8 Prob 0.002 0.344 0.126 0.363 0.137 DIPERS HDSMT ERTLPN LRTLPN STLLPN SCORE % NOT % NOT % NOT % NOT Stat ABS ABS ABS ABS ABS Mean1 3.7 35.8 69.8 100.0 57.5 Mean2 3.8 43.6 67.3 100.0 87.5 Locs 6 5 6 1 1 Reps 12 10 7 2 2 Diff −0.2 −7.8 2.4 0.0 −30.0 Prob 0.833 0.373 0.865 — —

TABLE 4 GENERAL COMBINING ABILITY REPORT FOR PHDWA PRM Day ABS Mean 114 PRM Day ABS Reps 2019 PRMSHD Day ABS Mean 114 PRMSHD Day ABS Reps 1417 YIELD bu/a 56# ABS Mean 193.2 YIELD bu/a 56# ABS Reps 1270 YIELD bu/a 56# ABS Years 3 YIELD bu/a 56# % MN Mean 101.5 YIELD bu/a 56# % MN Reps 1270 MST pct ABS Mean 21.8 MST pct ABS Reps 1280 MST pct % MN Mean 101 MST pct % MN Reps 1280 YLDMST ABS Mean 100.5 YLDMST ABS Reps 1273 STLPCN % NOT % MN Mean 101 STLPCN % NOT % MN Reps 255 STLLPN % NOT % MN Mean 103 STLLPN % NOT % MN Reps 268 ERTLPN % NOT % MN Mean 108 ERTLPN % NOT % MN Reps 146 LRTLPN % NOT % MN Mean 105 LRTLPN % NOT % MN Reps 284 TSTWT lb/bu % MN Mean 101.2 TSTWT lb/bu % MN Reps 895 STKCNT count % MN Mean 100 STKCNT count % MN Reps 2021 PLTHT in % MN Mean 98 PLTHT in % MN Reps 454 EARHT in % MN Mean 97 EARHT in % MN Reps 427 BRTSTK % NOT % MN Mean 101 BRTSTK % NOT % MN Reps 89 BORBMN % NOT % MN Mean 141 BORBMN % NOT % MN Reps 56 BRENGMN kg * mm Mean 101.9 % MN BRENGMN kg * mm Reps 22 % MN GLFSPT score ABS Mean 5 GLFSPT score ABS Reps 74 STAGRN score ABS Mean 5 STAGRN score ABS Reps 278 HSKCVR score ABS Mean 5 HSKCVR score ABS Reps 53 ECBLSI score ABS Mean 5.29 ECBLSI score ABS Reps 191

TABLE 5A INBREDS IN HYBRID COMBINATION REPORT Variety #1: HYBRID CONTAINING PHDWA Variety #2: 33Y45 YIELD YIELD MST EGRWTH ESTCNT GDUSHD BU/A 56# BU/A 56# PCT SCORE COUNT GDU Stat ABS % MN % MN % MN % MN % MN Mean1 202.0 104.1 104.7 90.4 96.4 102.2 Mean2 203.1 104.0 103.5 102.7 96.4 103.9 Locs 118 118 118 15 4 29 Reps 132 132 133 16 5 38 Diff −1.1 0.1 −1.2 −12.3 −0.1 −1.7 Prob 0.580 0.949 0.198 0.017 0.986 0.000 GDUSLK STKCNT PLTHT EARHT STAGRN STKLDG GDU COUNT CM CM SCORE % NOT Stat % MN % MN % MN % MN % MN % MN Mean1 102.0 99.5 100.4 99.8 124.0 112.6 Mean2 103.9 100.4 104.5 107.5 122.3 102.4 Locs 28 199 44 41 32 2 Reps 37 292 53 47 34 4 Diff −1.9 −0.9 −4.1 −7.7 1.7 10.2 Prob 0.000 0.016 0.000 0.000 0.789 0.295 STLLPN TSTWT GLFSPT NLFBLT SLFBLT GOSWLT % NOT LB/BU SCORE SCORE SCORE SCORE Stat % MN ABS ABS ABS ABS ABS Mean1 106.4 56.9 5.8 3.9 5.3 7.5 Mean2 119.5 56.6 6.1 4.7 5.3 7.0 Locs 17 81 9 12 3 3 Reps 31 91 14 18 4 6 Diff −13.1 0.3 −0.3 −0.8 0.0 0.5 Prob 0.081 0.096 0.508 0.014 1.000 0.478 ANTROT FUSERS DIPERS COMRST HSKCVR GIBROT SCORE SCORE SCORE SCORE SCORE SCORE Stat ABS ABS ABS ABS ABS ABS Mean1 4.4 5.2 3.7 2.5 4.9 5.0 Mean2 4.9 4.8 5.1 3.0 4.6 8.0 Locs 6 3 9 1 14 2 Reps 11 6 18 2 14 4 Diff −0.5 0.3 −1.3 −0.5 0.4 −3.0 Prob 0.275 0.423 0.004 — 0.239 0.105 DIPROT BRTSTK HDSMT ERTLPN LRTLPN STLPCN SCORE % NOT % NOT % NOT % NOT % NOT Stat ABS ABS ABS ABS ABS ABS Mean1 4.0 94.8 74.6 96.5 92.1 85.9 Mean2 4.5 97.3 88.2 93.1 90.2 85.9 Locs 1 13 8 9 28 28 Reps 2 19 22 11 34 34 Diff −0.5 −2.5 −13.6 3.4 2.0 0.0 Prob — 0.166 0.079 0.231 0.588 1.000

TABLE 5B INBREDS IN HYBRID COMBINATION REPORT Variety #1: HYBRID CONTAINING PHDWA Variety #2: 32K22 YIELD YIELD EGRWTH ESTCNT GDUSHD BU/A 56# BU/A 56# MST PCT SCORE COUNT GDU Stat ABS % MN % MN % MN % MN % MN Mean1 202.3 104.1 104.7 90.4 96.4 101.2 Mean2 201.7 103.4 104.8 109.4 94.8 99.9 Locs 116 116 116 15 4 25 Reps 131 131 131 16 5 34 Diff 0.7 0.7 0.1 −18.9 1.5 1.3 Prob 0.757 0.530 0.899 0.003 0.653 0.003 GDUSLK STKCNT PLTHT EARHT STAGRN STKLDG GDU COUNT CM CM SCORE % NOT Stat % MN % MN % MN % MN % MN % MN Mean1 100.9 99.3 100.4 99.8 123.9 112.6 Mean2 99.9 100.0 101.3 104.5 102.5 99.8 Locs 24 193 44 41 31 2 Reps 33 284 52 46 33 4 Diff 1.0 −0.6 −0.9 −4.7 21.4 12.8 Prob 0.040 0.116 0.157 0.000 0.002 0.295 STLLPN TSTWT GLFSPT NLFBLT SLFBLT GOSWLT % NOT LB/BU SCORE SCORE SCORE SCORE Stat % MN ABS ABS ABS ABS ABS Mean1 106.4 56.8 5.8 3.9 5.3 7.5 Mean2 110.0 56.7 4.8 4.2 4.8 6.7 Locs 17 77 9 12 3 3 Reps 31 88 15 18 4 6 Diff −3.6 0.1 1.0 −0.3 0.5 0.8 Prob 0.675 0.419 0.007 0.256 0.423 0.199 ANTROT FUSERS DIPERS COMRST HSKCVR GIBROT SCORE SCORE SCORE SCORE SCORE SCORE Stat ABS ABS ABS ABS ABS ABS Mean1 4.4 5.2 3.7 2.5 4.9 5.0 Mean2 4.1 5.7 4.9 3.0 5.7 6.5 Locs 6 3 9 1 14 2 Reps 11 6 17 2 14 4 Diff 0.3 −0.5 −1.2 −0.5 −0.8 −1.5 Prob 0.175 0.423 0.019 — 0.003 0.205 DIPROT BRTSTK HDSMT ERTLPN LRTLPN STLPCN SCORE % NOT % NOT % NOT % NOT % NOT Stat ABS ABS ABS ABS ABS ABS Mean1 4.0 94.8 74.6 96.5 92.1 86.5 Mean2 1.5 97.2 76.5 83.9 82.9 70.9 Locs 1 13 8 9 28 27 Reps 2 19 21 11 34 33 Diff 2.5 −2.4 −1.9 12.6 9.3 15.6 Prob — 0.314 0.752 0.174 0.033 0.004

TABLE 6 PHENOTYPIC DATA FROM HYBRIDS PRODUCED WITH PHDWA. PRM PRM YIELD YIELD YIELD YIELD YIELD PRM PRM SHD SHD bu/a bu/a bu/a bu/a bu/a Day Day Day Day 56# 56# 56# 56# 56# ABS ABS ABS ABS ABS ABS ABS % MN % MN MEAN REPS MEAN REPS MEAN REPS YRS MEAN REPS Hybrid 1 115 26 204 17 1 109.3 17 Hybrid 2 115 214 113 214 201.3 111 3 104.8 111 Hybrid 3 193.8 18 1 103.5 18 Hybrid 4 111 77 111 77 197.5 47 2 103.8 47 Hybrid 5 111 26 175.7 17 1 98.2 17 Hybrid 6 112 80 113 61 190.5 47 2 99.6 47 Hybrid 7 111 59 184.4 32 1 103.3 32 Hybrid 8 112 25 174.5 17 1 99.5 17 Hybrid 9 112 60 190.5 33 1 104 33 Hybrid 10 109 20 200.8 13 1 105.3 13 Hybrid 11 110 20 192.8 13 1 103 13 Hybrid 12 113 52 112 29 194.9 36 2 97.8 36 Hybrid 13 112 26 180.2 17 1 97.6 17 Hybrid 14 111 26 187.4 17 1 101.5 17 Hybrid 15 117 58 115 58 193.3 52 3 98.8 52 Hybrid 16 117 343 115 323 194.3 155 3 102.4 155 Hybrid 17 114 20 197 11 1 98.2 11 Hybrid 18 113 19 114 19 195 44 3 101.5 44 Hybrid 19 185.3 18 1 98.2 18 Hybrid 20 193.2 18 1 100.7 18 Hybrid 21 191.2 18 1 99.7 18 Hybrid 22 196.2 10 1 102 10 Hybrid 23 170.2 17 1 88.5 17 Hybrid 24 115 52 114 29 203.1 38 2 102.4 38 Hybrid 25 115 397 114 397 197.2 166 3 103.8 166 Hybrid 26 115 83 114 60 200.3 48 2 105.2 48 Hybrid 27 112 83 192.9 49 2 101.9 49 Hybrid 28 114 52 115 29 201.6 37 2 101.6 37 Hybrid 29 111 26 172 17 1 94.9 17 Hybrid 30 172.3 18 1 92 18 Hybrid 31 168.5 18 1 89.6 18 Hybrid 32 113 115 114 61 194 69 2 100.1 69 Hybrid 33 112 60 114 60 182.2 32 1 98.1 32 YLD YLD STL STL MST MST MST MST MST MST PCN PCN pct pct pct pct Value Value % NOT % NOT ABS ABS % MN % MN ABS ABS % MN % MN MEAN REPS MEAN REPS MEAN REPS MEAN REPS Hybrid 1 23.6 17 104.6 17 104.7 17 104 4 Hybrid 2 22.2 111 102.2 111 102.6 111 95 30 Hybrid 3 21.9 18 96.1 18 107.3 18 49 4 Hybrid 4 21.5 47 97.7 47 106.1 47 128 7 Hybrid 5 19.9 17 96.2 17 102 17 111 3 Hybrid 6 20.3 47 99.2 47 100.4 47 104 4 Hybrid 7 21.2 32 108.5 32 94.7 34 88 3 Hybrid 8 21.5 17 100.7 17 98.9 17 84 4 Hybrid 9 20.9 33 101.9 33 102.1 33 111 11 Hybrid 10 19.4 13 103.1 13 102.2 13 97 2 Hybrid 11 20.2 13 102.7 13 100.3 13 50 2 Hybrid 12 21.5 36 96.6 36 101.2 36 123 1 Hybrid 13 20.7 17 93 17 104.6 17 103 3 Hybrid 14 20.5 17 92.1 17 109.4 17 103 3 Hybrid 15 22.9 52 103.7 52 95.2 52 102 8 Hybrid 16 22.1 160 101.7 160 100.4 155 91 25 Hybrid 17 23.1 14 99.6 14 98 11 Hybrid 18 22.5 44 100.7 44 100.8 44 86 9 Hybrid 19 22.7 18 99.1 18 99.1 18 70 4 Hybrid 20 22.5 18 101.6 18 99 18 120 2 Hybrid 21 21.4 18 97.2 18 102.5 18 127 2 Hybrid 22 22.8 10 104.1 10 97.9 10 Hybrid 23 22.1 17 99.5 17 88.9 17 120 1 Hybrid 24 21.9 38 100.1 38 102.3 38 122 8 Hybrid 25 22.5 168 105.4 168 98.6 167 121 41 Hybrid 26 22.3 48 103.7 48 101.5 48 99 14 Hybrid 27 21 49 100.5 49 101.4 49 111 18 Hybrid 28 21.8 37 99.6 37 102 37 90 8 Hybrid 29 20.3 17 97.5 17 97.5 17 91 4 Hybrid 30 22.2 18 97.3 18 94.7 18 103 4 Hybrid 31 21.9 18 95.7 18 93.9 18 78 4 Hybrid 32 21.4 69 100 69 100.1 69 104 11 Hybrid 33 20.6 32 94.9 32 103.1 32 71 11 STL STL ERT ERT LRT LRT TST TST LPN LPN LPN LPN LPN LPN WT WT % NOT % NOT % NOT % NOT % NOT % NOT lb/bu lb/bu % MN % MN % MN % MN % MN % MN % MN % MN MEAN REPS MEAN REPS MEAN REPS MEAN REPS Hybrid 1 114 6 86 3 105 5 99.6 11 Hybrid 2 92 24 98 9 110 12 100.3 82 Hybrid 3 112 2 116 2 100.2 18 Hybrid 4 113 16 100 7 98 8 100.7 29 Hybrid 5 93 6 88 4 102 7 101.4 10 Hybrid 6 116 7 122 5 91 12 101 28 Hybrid 7 101 10 108 3 86 3 99.2 24 Hybrid 8 82 4 103 4 95 4 100.2 12 Hybrid 9 110 7 113 5 106 8 100.2 23 Hybrid 10 105 5 103 3 102.2 12 Hybrid 11 88 5 106 4 100.9 12 Hybrid 12 102 8 100 3 111 5 102.1 20 Hybrid 13 106 6 112 3 105 9 102.2 10 Hybrid 14 93 6 81 3 97 9 102.6 10 Hybrid 15 118 15 108 6 107 8 100.8 24 Hybrid 16 93 37 126 22 102 50 101.4 112 Hybrid 17 151 4 109 10 101.5 14 Hybrid 18 90 9 104 6 110 4 101.8 29 Hybrid 19 109 2 116 2 103 18 Hybrid 20 34 2 102 16 Hybrid 21 45 2 101.8 16 Hybrid 22 101.8 8 Hybrid 23 84 2 101.5 15 Hybrid 24 120 6 114 4 102 9 102.3 22 Hybrid 25 109 43 111 15 116 38 100.9 113 Hybrid 26 88 9 111 9 111 9 100.8 34 Hybrid 27 108 10 99 6 111 14 100.7 34 Hybrid 28 105 6 96 4 103 9 101.2 21 Hybrid 29 111 6 120 3 102 8 100.2 10 Hybrid 30 112 2 122 2 101.9 18 Hybrid 31 112 2 122 2 102.6 18 Hybrid 32 104 9 88 5 112 14 102 49 Hybrid 33 100 8 70 5 84 8 103.3 23 STK STK BRT BRT CNT CNT PLTHT PLTHT STK STK count count in in EAR HT EAR HT % NOT % NOT % MN % MN % MN % MN in % MN in % MN % MN % MN MEAN REPS MEAN REPS MEAN REPS MEAN REPS Hybrid 1 100 23 98 6 101 6 Hybrid 2 101 200 100 36 94 29 101 16 Hybrid 3 99 18 93 4 88 4 Hybrid 4 101 70 98 18 95 18 101 5 Hybrid 5 101 23 93 6 97 6 Hybrid 6 101 75 100 18 99 17 98 1 Hybrid 7 100 57 100 8 101 8 109 2 Hybrid 8 101 23 96 7 92 7 Hybrid 9 100 53 100 14 97 14 Hybrid 10 101 19 101 7 104 7 Hybrid 11 101 19 97 7 101 7 Hybrid 12 101 50 96 11 98 11 103 5 Hybrid 13 101 23 100 6 96 6 Hybrid 14 100 23 98 6 96 6 Hybrid 15 100 77 97 22 99 21 101 4 Hybrid 16 100 311 96 52 96 46 103 18 Hybrid 17 100 18 Hybrid 18 99 57 98 19 93 18 101 4 Hybrid 19 100 18 96 4 88 4 Hybrid 20 100 18 101 4 106 4 Hybrid 21 100 18 103 4 102 4 Hybrid 22 102 10 Hybrid 23 101 17 98 4 98 4 Hybrid 24 100 48 99 14 97 13 101 2 Hybrid 25 99 338 100 70 99 64 97 20 Hybrid 26 101 72 99 21 100 20 Hybrid 27 99 75 98 21 93 20 93 2 Hybrid 28 100 48 99 14 98 13 98 2 Hybrid 29 100 23 101 6 98 6 Hybrid 30 101 18 97 4 89 4 Hybrid 31 101 18 95 4 89 4 Hybrid 32 100 108 96 21 95 20 103 8 Hybrid 33 100 53 99 16 104 16 BOR BOR BREN BREN GLF GLF BMN BMN GMN GMN SPT SPT % NOT % NOT kg * mm kg * mm score score % MN % MN % MN % MN ABS ABS MEAN REPS MEAN REPS MEAN REPS Hybrid 1 4 1 Hybrid 2 105.1 6 5 10 Hybrid 3 Hybrid 4 6 3 Hybrid 5 5 1 Hybrid 6 151 4 5 1 Hybrid 7 133 6 4 3 Hybrid 8 5 1 Hybrid 9 135 6 6 2 Hybrid 10 4 1 Hybrid 11 4 1 Hybrid 12 Hybrid 13 4 1 Hybrid 14 4 1 Hybrid 15 4 1 Hybrid 16 161 4 97.6 6 6 14 Hybrid 17 6 2 Hybrid 18 4 1 Hybrid 19 Hybrid 20 Hybrid 21 Hybrid 22 Hybrid 23 Hybrid 24 5 1 Hybrid 25 134 12  94.9 6 6 19 Hybrid 26 151 6 5 2 Hybrid 27 133 6 5 3 Hybrid 28 5 1 Hybrid 29 3 1 Hybrid 30 Hybrid 31 Hybrid 32 143 6 114 4 5 1 Hybrid 33 142 6 6 2 STA STA HSK HSK ECB ECB GRN GRN CVR CVR LSI LSI score score score score score score ABS ABS ABS ABS ABS ABS MEAN REPS MEAN REPS MEAN REPS Hybrid 1 5 1 6.7 3 Hybrid 2 5 32 4 6 4.4 9 Hybrid 3 4 4 Hybrid 4 4 11 5.9 10 Hybrid 5 3 1 4.5 2 Hybrid 6 4 10 4.3 7 Hybrid 7 5 5 6 1 5 2 Hybrid 8 5 4 5 1 6.3 3 Hybrid 9 5 10 6 1 5.3 8 Hybrid 10 4 4 Hybrid 11 3 5 Hybrid 12 4 5 5.8 12 Hybrid 13 4 1 5.5 4 Hybrid 14 3 1 5 4 Hybrid 15 5 10 4 4 5.7 18 Hybrid 16 5 19 6 16 5.4 20 Hybrid 17 Hybrid 18 4 11 6 4 4.9 7 Hybrid 19 3 4 Hybrid 20 4 8 Hybrid 21 4 8 Hybrid 22 4 6 Hybrid 23 4 8 Hybrid 24 4 7 5.4 12 Hybrid 25 6 42 5 16 5.6 21 Hybrid 26 4 12 5 1 4.3 8 Hybrid 27 4 14 6 1 5.7 10 Hybrid 28 4 7 5.8 12 Hybrid 29 1 1 5.3 3 Hybrid 30 5 4 Hybrid 31 6 4 Hybrid 32 5 10 7 1 4.6 10 Hybrid 33 4 9 4 1 4.8 6

All publications, patents and patent applications mentioned in the specification are indicative of the level of those skilled in the art to which this invention pertains. All such publications, patents and patent applications are incorporated by reference herein for the purpose cited to the same extent as if each was specifically and individually indicated to be incorporated by reference herein.

The foregoing invention has been described in detail by way of illustration and example for purposes of clarity and understanding. As is readily apparent to one skilled in the art, the foregoing are only some of the methods and compositions that illustrate the embodiments of the foregoing invention. It will be apparent to those of ordinary skill in the art that variations, changes, modifications and alterations may be applied to the compositions and/or methods described herein without departing from the true spirit, concept and scope of the invention 

1. A seed comprising at least one set of the chromosomes of maize inbred line PHDWA, representative seed of said line having been deposited under ATCC Accession Number PTA-7766, wherein said chromosomes comprise all of the alleles of inbred line PHDWA at the SSR loci listed in Table
 2. 2. A maize plant produced by growing the seed of claim
 1. 3. A maize plant part of the maize plant of claim
 2. 4. The seed of claim 1, wherein said seed is an F1 hybrid maize seed produced by crossing a plant of maize inbred line PHDWA with a different maize plant and harvesting the resultant F1 hybrid maize seed.
 5. A maize plant produced by growing the F1 hybrid maize seed of claim
 4. 6. A maize plant part of the maize plant of claim
 5. 7. An F1 hybrid maize seed comprising an inbred maize plant cell of inbred maize line PHDWA, representative seed of said line having been deposited under ATCC Accession Number PTA-7766.
 8. A maize plant produced by growing the F1 hybrid maize seed of claim
 7. 9. The F1 hybrid maize seed of claim 7 wherein the inbred maize plant cell comprises two sets of chromosomes of maize inbred line PHDWA, wherein said chromosomes comprise all of the alleles of inbred line PHDWA at the SSR loci listed in Table
 2. 10. A maize plant produced by growing the F1 hybrid maize seed of claim
 9. 11. A process of introducing a desired trait into maize inbred line PHDWA comprising: (a) crossing PHDWA plants grown from PHDWA seed, representative seed of which has been deposited under ATCC Accession Number PTA-7766, with plants of another maize line that comprise a desired trait to produce F1 progeny plants, wherein the desired trait is selected from the group consisting of waxy starch, male sterility, herbicide resistance, insect resistance, bacterial disease resistance, fungal disease resistance, and viral disease resistance; (b) selecting F1 progeny plants that have the desired trait to produce selected F1 progeny plants; (c) crossing the selected progeny plants with the PHDWA plants to produce backcross progeny plants; (d) selecting for backcross progeny plants that have the desired trait and the alleles of inbred line PHDWA at the SSR loci listed in Table 2 to produce selected backcross progeny plants; and (e) repeating steps (c) and (d) to produce backcross progeny plants that comprise the desired trait and comprise at least 95% of the alleles of inbred line PHDWA at the SSR loci listed in Table
 2. 12. A plant produced by the process of claim 11, wherein the plant comprises at least 95% of the alleles of inbred line PHDWA at the SSR loci listed in Table
 2. 13. A maize plant having all the physiological and morphological characteristics of inbred line PHDWA, wherein a sample of the seed of inbred line PHDWA was deposited under ATCC Accession Number PTA-7766.
 14. A process of producing maize seed, comprising crossing a first parent maize plant with a second parent maize plant, wherein one or both of the first or the second parent maize plants is the plant of claim 13, and harvesting the resultant seed.
 15. The maize seed produced by the process of claim
 14. 16. The maize seed of claim 15, wherein the maize seed is hybrid seed.
 17. A hybrid maize plant, or its parts, produced by growing said hybrid seed of claim
 16. 18. The maize plant of claim 13, further comprising an SSR profile in accordance with the profile shown in Table
 2. 19. A cell of the maize plant of claim
 13. 20. The cell of claim 19, wherein said cell is further defined as having an SSR profile in accordance with the profile shown in Table
 2. 21. A seed comprising the cell of claim
 19. 22. The maize plant of claim 13, further defined as having a genome comprising a single locus conversion.
 23. The maize plant of claim 22, wherein the single locus was stably inserted into the maize genome by transformation.
 24. The maize plant of claim 22, wherein the locus is selected from the group consisting of a dominant allele and a recessive allele.
 25. The maize plant of claim 22, wherein the locus confers a trait selected from the group consisting of herbicide tolerance; insect resistance; resistance to bacterial, fungal, nematode or viral disease; waxy starch; male sterility and restoration of male fertility.
 26. The maize plant of claim 13, wherein said plant is further defined as comprising a gene conferring male sterility.
 27. The maize plant of claim 13, wherein said plant is further defined as comprising a transgene conferring a trait selected from the group consisting of male sterility, herbicide resistance, insect resistance, and disease resistance.
 28. A method of producing a maize plant comprising the steps of: (a) growing a progeny plant produced by crossing the plant of claim 13 with a second maize plant; (b) crossing the progeny plant with itself or a different plant to produce a seed of a progeny plant of a subsequent generation; (c) growing a progeny plant of a subsequent generation from said seed and crossing the progeny plant of a subsequent generation with itself or a different plant; and (d) repeating steps (b) and (c) for an additional 0-5 generations to produce a maize plant.
 29. The method of claim 28 wherein the produced maize plant is an inbred maize plant.
 30. The method of claim 29, further comprising the step of crossing the inbred maize plant with a second, distinct inbred maize plant to produce an F1 hybrid maize plant.
 31. A method for developing a second maize plant in a maize plant breeding program comprising applying plant breeding techniques to a first maize plant, or parts thereof, wherein said first maize plant is the maize plant of claim 13, and wherein application of said techniques result in development of said second maize plant.
 32. The method for developing a maize plant in a maize plant breeding program of claim 31 wherein plant breeding techniques are selected from the group consisting of recurrent selection, backcrossing, pedigree breeding, restriction fragment length polymorphism enhanced selection, genetic marker enhanced selection, and transformation.
 33. A method of plant breeding comprising the steps of: (a) obtaining the molecular marker profile of maize inbred line PHDWA, representative seed of said line having been deposited under ATCC Accession No. PTA-7766; (b) obtaining an F1 hybrid seed for which the maize plant of claim 13 is a parent; (c) crossing a plant grown from the F1 hybrid seed with a different maize plant; and (d) selecting progeny that retain the molecular marker profile of PHDWA. 